ESIT 2024: Gathering of Global Minds to Hangzhou for Cutting-Edge Infrared and Terahertz Innovation
Welcome to our new Editorial Board Members Prof. Manijeh Razeghi
Welcome to our new Editorial Board Members Dr. He Zhiping
Welcome to our new Editorial Board Members Dr. Jun Ge
Welcome to our new Editorial Board Members Dr. Ye Zhenhua
Welcome to our new Editorial Board Members Dr. Chen Fansheng
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HOU Zhi-Jin, CHEN Yan, WANG Xu-Dong, WANG Jian-Lu, CHU Jun-Hao
2024,43(5):589-594, DOI: 10.11972/j.issn.1001-9014.2024.05.001
Abstract:
Silicon （Si） diffraction microlens arrays are usually used to integrate with infrared focal plane arrays （IRFPAs） to improve their performance. The errors of lithography are unavoidable in the process of the Si diffraction microlens arrays preparation in the conventional engraving method. It has a serious impact on its performance and subsequent applications. In response to the problem of errors of Si diffraction microlens arrays in the conventional method， a novel self-alignment method for high precision Si diffraction microlens arrays preparation is proposed. The accuracy of the Si diffractive microlens arrays preparation is determined by the accuracy of the first lithography mask in the novel self-alignment method. In the subsequent etching， the etched area will be protected by the mask layer and the sacrifice layer or the protective layer. The unprotection area is carved to effectively block the non-etching areas， accurately etch the etching area required， and solve the problem of errors. The high precision Si diffraction microlens arrays are obtained by the novel self-alignment method and the diffraction efficiency could reach 92.6%. After integrating with IRFPAs， the average blackbody responsity increased by 8.3%， and the average blackbody detectivity increased by 10.3%. It indicates that the Si diffraction microlens arrays can improve the filling factor and reduce the crosstalk of IRFPAs through convergence， thereby improving the performance of IRFPAs. The results are of great reference significance for improving their performance through optimizing the preparation level of micro nano devices.
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LIU Mao-Fan, YU Chun-Lei, MA Ying-Jie, YU Yi-Zhen, YANG Bo, TIAN Yu, BAO Peng-Fei, CAO Jia-Sheng, LIU Yi, LI Xue
2024,43(5):595-602, DOI: 10.11972/j.issn.1001-9014.2024.05.002
Abstract:
The development of InGaAs/InP single-photon avalanche photodiodes （SPADs） necessitates the utilization of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the distribution of its electric field. Regarding the issue of accurately predicting the depth of diffusion in InGaAs/InP SPAD， simulation analysis and device development were carried out， focusing on the dual diffusion behavior of zinc atoms. A formula of
to quantitatively predict the diffusion depth is obtained by fitting the simulated twice-diffusion depths based on a two-dimensional （2D） model. The 2D impurity morphologies and the one-dimensional impurity profiles for the dual-diffused region are characterized by using scanning electron microscopy and secondary ion mass spectrometry as a function of the diffusion depth， respectively. InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated， which show breakdown behaviors are well consistent with the simulated results under the same junction geometries. The dark count rate （DCR） of the device decreased as the multiplication width increased， as indicated by the results. DCRs of 2 106， 1 105， 4 104， and 2 104 were achieved at temperatures of 300 K， 273 K， 263 K， and 253 K， respectively， with a bias voltage of 3 V， when the multiplication width was 1.5 μm. These results demonstrate an effective prediction route for accurately controlling the dual-diffused zinc junction geometry in InP-based planar device processing. - 1
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LI Yun-Peng, LUO Jia-Cheng, JI Ruo-Nan, XIE Mao-Bin, CUI Wen-Nan, WANG Shao-Wei, LIU Feng, LU Wei
2024,43(5):603-608, DOI: 10.11972/j.issn.1001-9014.2024.05.003
Abstract:
Metasurfaces in the long wave infrared （LWIR） spectrum hold great potential for applications in thermal imaging， atmospheric remote sensing， and target identification， among others. In this study， we designed and experimentally demonstrated a 4 mm size， all-silicon metasurface metalens with large depth of focus operational across a broadband range from 9 μm to 11.5 μm. The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region， thus paving the way for practical LWIR applications of metalens technology.
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WAN Jing, YU Ting-Jie, CHEN Jian-Song, ZHOU Rui, WAN Hong-Dan
2024,43(5):609-614, DOI: 10.11972/j.issn.1001-9014.2024.05.004
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Variable optical attenuator （VOA） arrays can be widely applied in optical communication and optoelectronic systems， but few VOA arrays are reported. Here a liquid-stop based microfluidic VOA array is proposed. It uses a spiral orbit to achieve different degrees of synchronous energy attenuation of multiple beams， or uses an annular orbit to achieve a same degree of synchronous energy attenuations， where the clear aperture of liquid stop is regulated by the electrowetting-on-dielectric effect. It has a compact structure， small volume， simple operation and low cost. Meanwhile， the attenuation ratio of beams can be flexibly adjusted to achieve the power equalization. The research results indicate that the VOA array has a wide attenuation range （0-100% attenuation） and very small insertion loss （0.26 dB） over general VOA arrays. The response time is 0.1 ms， and it is insensitive to the polarization. It can also act as an optical switch array. The proposed VOA array demonstrates the potential of integration and high performance， and it can provide a cost-effective way for applications.
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ZHAN Jia, ZHA Fang-Xing, GU Yi
2024,43(5):615-620, DOI: 10.11972/j.issn.1001-9014.2024.05.005
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Photoreflectance （PR） has been widely used for the characterization of various semiconductors as well as their surface and interface properties due to its non-destructive and high sensitivity virtues. From the viewpoint of the employment of monochromator， the experimental setup may be classified into dark and bright configurations， which were applied to characterize the heterostructure of InP/In0.52Ga0.48As/InP grown by molecular beam epitaxy. It reveals that the front configuration well separates the luminescence from the modulation signal while the backside configuration benefits the extraction of weak modulation signals with the employment of high excitation power. Based on the backside configuration， we also observed a below band-gap excitation phenomenon， i.e. that the modulation signal of InP exhibits under the excitation of energetically low modulation light （1 064 nm laser）. The result demonstrates that the backside configuration may be employed as a contactless electro-modulation technique for the characterization of wide band gap semiconductor heterostructures.
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YANG Jun, YANG Chun-Li, FANG Hui, YUAN Jun, YAN Shan-Ru, LI Hua-Ying, LI Bing-Zhe
2024,43(5):621-627, DOI: 10.11972/j.issn.1001-9014.2024.05.006
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As the cell size of uncooled infrared （IR） detectors progressively shrinks， it becomes increasingly important to increase detector absorption. here， an IMIAM （Insulator-Metal-Insulator-Air-Metal） cavity type metasurface uncooled IR detector structure is proposed， which effectively improves the uniformity of the photosensitive layer while enhancing the absorption of the detector. Utilizing systematic simulation and optimization， it has achieved almost perfect absorption in the Long Wavelength Infrared range （8~14 μm）， meanwhile， it also shows excellent absorption performance in Mid Wavelength Infrared band. In this paper， the reliability of the structure is also verified by the process. this research may provide alternatives for optimizing conventional uncooled IR detectors
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JIN Zhao, RONG Yu, QIAO Li-Ping, YU Jing-Dong, WU Fei, GUO Chen, TIAN Dou
2024,43(5):628-633, DOI: 10.11972/j.issn.1001-9014.2024.05.007
Abstract:
In this paper， a dual-band graphene-based frequency selective surface （GFSS） is investigated and the operating mechanism of this GFSS is analyzed. By adjusting the bias voltage to control the graphene chemical potential between 0 eV and 0.5 eV， the GFSS can achieve four working states： dual-band passband， high-pass low-impedance， low-pass high-impedance， and band-stop. Based on this GFSS， a hexagonal radome on a broadband omnidirectional monopole antenna is proposed， which can achieve independent 360° six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands. In addition， while increasing the directionality， the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi， respectively. This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.
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JIANG Lu-Han, MA Han-Song, ZHANG Qin-Yi, TIAN Peng, HAN Yang, WANG Ming-Xu, TAN Jing-Wen, XU Si-Cong, ZHANG Bing, Rehim Uddim, WEI Yi, YANG Xiong-Wei, LI Wei-Ping, YU Jian-Jun
2024,43(5):634-641, DOI: 10.11972/j.issn.1001-9014.2024.05.008
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To meet the high-speed and high-capacity demands of communication， a 300GHz electronic wireless transmission system for terahertz frequencies is proposed， which incorporates Probability Shaping （PS）， Discrete Multi-tone Modulation （DMT） and DFT-Spread （DFT-S） techniques. PS increases the Euclidean distance between constellation points， thereby enhancing the receiver sensitivity. In the system at most 55% bit error rate is decreased， enabling to extend transmission range. DFT-S technique reduces 1.68 dB peak-to-average power ratio of Orthogonal Frequency Division Multiplexing （OFDM） signals in the system， thus improving their resistance to nonlinear effects. By integrating these advanced digital signal processing techniques， 12GBaud PS-16QAM OFDM-DMT signals and 10GBaud PS-64QAM DFT-S-OFDM-DMT signals were successfully implemented in 1 m wireless transmission. Finally， the performance advantages of these digital signal processing techniques were compared.
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GUO Yuan-Sen, CHEN Li-Gang, YAN Shi-Han, FU Ying, QIU Fu-Cheng, YANG Zhong-Bo, ZHANG Ming-Kun, TANG Ming-Jie, WANG Hua-Bin
2024,43(5):642-656, DOI: 10.11972/j.issn.1001-9014.2024.05.009
Abstract:
Terahertz （THz） technology is undergoing a rapid development in biomedical applications. Researchers have made a series of important achievements in the study of biological samples on various levels such as biomolecules， cells， tissues， and individual organisms， which provide new insights and innovative approaches for biological research and biomedical diagnosis. In this review， the progress of applying THz technology in biomedical studies has been summarized， including three key aspects， namely， spectroscopic detection， imaging， and biological effects. The challenges encountered in THz biomedical applications have been discussed， and the future development directions have also been envisioned.
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LI Yi-Qi, SUN Xiao-Bing, HUANG Hong-Lian, LIU Xiao, TI Ru-Fang, ZHENG Xiao-Bing, FAN Yi-Zhe, YU Hai-Xiao, WEI Yi-Chen, WANG Yu-Xuan, WANG Yu-Yao
2024,43(5):657-670, DOI: 10.11972/j.issn.1001-9014.2024.05.010
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The variations in extinction and microphysical properties in the upper haze of Venus have a significant impact on the chemistry and radiative balance of its atmosphere. In order to study their spatial and temporal distribution， we analyzed solar occultation data from the Venus Express SPICAV SOIR instruments between 2006 and 2013. To remove the absorption effects of the middle and upper atmosphere of Venus， we used MODTRAN modeling. Then， we retrieved the extinction profiles of the upper haze between 67-92 km using the onion-peeling method. Our findings are as follows： 1） The extinction coefficient of the upper haze generally decreases with increasing altitude， but there are significant variations between different regions. In low latitudes， the extinction increased sharply early in the mission， and the average extinction coefficient of the haze showed minimal changes between day and night. The vertical optical depth of the haze layer was approximately 10-2. 2） The number density of the upper haze decreases with increasing altitude. From the south to the north pole， the number density first increases and then decreases. 3） The cloud top altitude is higher in low-latitude regions at 82.7 ± 5.8 km， while in polar regions， it is lower with the northern polar region at 73.3 ± 2.4 km and the southern polar region at 79.5 ± 3.5 km. The average scale height of the upper haze layer in the northern polar region is 4.0 ± 0.9 km.
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HUI Zhan-Qiang, LI Jia-Ying, LI Tian-Tian, HAN Dong-Dong, GONG Jia-Min
2024,43(5):671-683, DOI: 10.11972/j.issn.1001-9014.2024.05.011
Abstract:
Optical coherence tomography （OCT） technology has the advantages of non-invasive， high-resolution， and real-time imaging， which is widely used in various fields such as biomedicine， material science and infrared sensing. A ridge suspended optical waveguide based on silicon nitride （Si3N4） is proposed. The structural parameters of the designed waveguide were optimized by using finite difference time domain （FDTD） method. The characteristics of the supercontinuum spectrum generated in the optimized waveguide were investigated The simulation results show that for the optimized optical waveguide structure with ridge width of 750 nm， ridge height of 700nm， plate thickness of 200 nm， and upper layer height of 150 nm， when a pump light with wavelength of 1.3μm， peak power of 2 kW and pulse width of 50 fs was injected into the waveguide， a broadband supercontinuum spectrum with wavelength covering the visible to the mid-infrared region （703~4014 nm） can be generated. This work plays an important role in promoting the application of on-chip integrated broadband light source in biomedical imaging and related fields.
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2024,43(5):684-695, DOI: 10.11972/j.issn.1001-9014.2024.05.012
Abstract:
Remote sensing image scene classification aims to automatically assign a semantic label to each remote sensing image according to its content， and has become one of the hot topics in the field of remote sensing image processing. Methods based on convolutional neural networks （CNNs） and methods based on self-attention mechanism are two mainstream methods in remote sensing image scene classification. However， the former is less effective in exploring long-range contextual information， and the latter has limitations in learning local information and has a large number of parameters and calculations. In order to address these issues， a lightweight method based on knowledge distillation is proposed to solve the problem of scene classification for remote sensing images. The proposed method uses Swin Transformer and lightweight CNNs as the teacher model and the student models， respectively， and integrates the advantages of the two kinds of models by means of knowledge distillation. Furthermore， a novel distillation loss function is proposed to enable the student models to focus on both inter- and intra-class potential information of remote sensing images simultaneously. The experimental results on two large-scale remote sensing image datasets demonstrate that the proposed method not only achieves high classification accuracy compared to existing methods but also has a significantly reduced number of parameters and calculations.
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YANG Yu, LONG Ming-Liang, ZHANG Hai-Feng, ZHANG Xiao-Xiang, HUANG Xing-Min, DING Jie, LI Pu, DENG Hua-Rong, ZHANG Zhong-Ping
2024,43(5):696-702, DOI: 10.11972/j.issn.1001-9014.2024.05.013
Abstract:
High-precision space debris measurements can provide more accurate real-time information on debris targets and enhance the effectiveness of satellite avoidance warnings for space debris. Through the modification of the 1.2 m aperture quantum communication telescope （altitude 3200 m） in Qinghai Province， the satellite laser ranging （SLR） and space debris laser ranging （DLR） experiments were carried out by using a single pulse energy of 1.2 mJ and a repetition rate of 1 kHz picosecond laser， in which the detection range of cooperative satellites has been extended from Low Earth Orbit to Geosynchronous Eearth Orbit， and the ranging accuracy was better than 2 cm. The maximum distance of space debris target measurement is 1620.5 km， the radar cross section （RCS） is 2.41 m2， and the ranging accuracy reaches 10.64 cm.A single laser system has been realized， which can not only carry out centimeter-level high-precision ranging of cooperative targets， but also realize space debris observation. This is the first time in the world to use high repetition frequency and low power laser ranging system to achieve high precision measurement of space debris targets， reflecting the advantages of picosecond laser and high-altitude large-aperture telescope measurement， providing reference for developing space target laser ranging in western China， and providing an effective way for space debris laser ranging system site selection and space debris monitoring capability enhancement.
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WANG Zhong, SUN Sheng-Li, CHEN Rui, MA Yi-Jun, XU Wen-Jun, ZHANG Ya-Feng
2024,43(5):703-721, DOI: 10.11972/j.issn.1001-9014.2024.05.014
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Through sufficient investigation and summary， the development trend and representative work of Metaverse and related technologies in the aerospace field since the 1960s have been sorted out， and it is pointed out that multi-satellite networking， digitalization and virtualization will become important development trends of aerospace science and technology. Hence， a new concept called “Aerospace Metaverse” has been proposed. Based on this concept， the fundamentals of mathematics and physics have been analyzed. Necessry technologies to build Aerospace Metaverse such as digital twins of aerospace and wide domain ultra high speed intelligent perceptionhave been proposed， and their implementation approaches are elaborated. Furthermore， combining with the vigorous development of aerospace technology， scenarios that can be first put into use have been predicted. Several existing difficulties in building Aerospace Metaverse and corresponding solutions have been proposed， providing new ideas for the development of aerospace technology. Finally， an outlook has been made on the future development of Aerospace Metaverse.
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CHEN Chen, TONG Xiao-Hua, LIU Shi-Jie, YE Zhen, HUANG Chao-Wei, WU Hao, ZHANG Han
2024,43(5):722-730, DOI: 10.11972/j.issn.1001-9014.2024.05.015
Abstract:
The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevitably affected by the orbiter attitude jitter. Therefore， it is necessary to conduct preliminary research on the stereo mapping camera equipped on lunar orbiter before launching. In this work， an imaging simulation method considering the attitude jitter is presented. The impact analysis of different attitude jitter on terrain undulation is conducted by simulating jitter at three attitude angles， respectively. The proposed simulation method is based on the rigorous sensor model， using the lunar digital elevation model （DEM） and orthoimage as reference data. The orbit and attitude of the lunar stereo mapping camera are simulated while considering the attitude jitter. Two-dimensional simulated stereo images are generated according to the position and attitude of the orbiter in a given orbit. Experimental analyses were conducted by the DEM with the simulated stereo image. The simulation imaging results demonstrate that the proposed method can ensure imaging efficiency without losing the accuracy of topographic mapping. The effect of attitude jitter on the stereo mapping accuracy of the simulated images was analyzed through a DEM comparison.
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Volume 43,2024 Issue 5
Infrared Physics, Materials and Devices
Millimeter Waves and Terahertz Technology
Infrared Spectroscopy and Remote Sensing Technology
Remote Sensing Technology and Application
Infrared Optoelectronic System and Application Technology
Interdisciplinary Research on Infrared Science
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ZENG Dan, WEI Jian-Ming, ZHANG Jun-Jie, CHANG Liang, HUANG Wei
DOI: 10.11972/j.issn.1001-9014.2024.06.017
Abstract:
To avoid the accumulation of estimation errors from explicitly aligning multi-frame features in current infrared small-dim target detection algorithms， and to alleviate the loss of target features due to network downsampling， a progressive spatio-temporal feature fusion network is proposed. The network utilizes a progressive temporal feature accumulation module to implicitly aggregate multi-frame information and utilizes a multi-scale spatial feature fusion module to enhance the interaction between shallow detail features and deep semantic features. Due to the scarcity of multi-frame infrared dim target datasets， a highly realistic semi-synthetic dataset is constructed. Compared to the mainstream algorithms， the proposed algorithm improves the probability of detection by 4.69% and 4.22% on the proposed dataset and the public dataset， respectively.
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WANG Hao-Miao, HE Yu-Wen, LI Yi, HU Yao, ZHANG Liang, DU Wei-Chuan, GAO Song-Xin, TANG Chun, MA Xiao-Yu, LIU Su-Ping
DOI: 10.11972/j.issn.1001-9014.2024.06.006
Abstract:
The master oscillator power amplifier （MOPA） laser is receiving increasing attention due to its ability to achieve high power and beam quality output. In order to improve the polarization degree of MOPA laser and reduce the efficiency loss during polarization combining， InGaAs/AlGaAs compressive single quantum well was used in the active region. The optical confinement factor of TE-mode in ridge waveguide was improved by 1.35 μm deep etching， whereas the TE optical gain in tapered amplifier was increased through on-chip metal stress regulation. Combining the two schemes not only improves the degrees of polarization （DOP） of two sections， but also reduces the polarization angle difference. Finally， 11W@15A continuous output and over 90% DOP of the MOPA have been achieved by standard process fabrication.
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ZENG Chang-Wen, YANG Zhi-Yu, DAI Zuo-Xiao, GU Ming-Jian
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
The three-dimensional perception of road objects in challenging environments is crucial for the development of autonomous vehicles that operating in all conditions， at all hours. Infrared binocular vision mimics the human binocular system， facilitating stereoscopic perception of objects in challenging conditions such as dim or zero-light environments. The core technology for stereoscopic perception in binocular vision systems is accurate object detection and matching. To streamline the complex sequence of object detection and matching procedures， a synchronous object detection and matching network （SODMNet） is proposed， which can perform synchronous detection and matching of infrared objects. SODMNet innovatively combines an object detection network with an object matching module， leveraging the deep features from the classification and regression branches as inputs for the object matching module. By concatenating these features with relative position encoding from the feature maps and processing the concatenated features through a convolutional network， the network generates feature descriptors for the left and right images. Object matching is then achieved by calculating the Euclidean distances between these descriptors， thus facilitating synchronous object detection and matching in binocular vision. In addition， a novel nighttime infrared binocular dataset， annotated with targets such as pedestrians and vehicles， is created to support the development and evaluation of the proposed network. Experimental results indicate that SODMNet achieves a significant improvement of more than 84.9% in object detection mean average precision （mAP） on this dataset， with an object matching average precision （AP） of 0.5777. These results demonstrate that SODMNet is capable of high-precision， synchronized object detection and matching in infrared binocular vision， marking a significant advancement in the field.
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XU Xiang-Qian, GONG Guang-Yu, SUN Lei, LI Yu, Kang Xiao-Chen, LI Si-Min, PAN Shi-Long
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
This paper presents an innovative three-dimensional （3D） heterogeneously integrated photoreceiver， which is optimized for analog microwave optical links that demand both wide bandwidth and high input optical power. The key of this design is the uni-traveling-carrier photodiode （UTC-PD）， which has been flip-chip integrated onto a microwave integrated circuit submount. This integration approach enhances the photoreceiver"s bandwidth and high power handling capabilities. The material doping and epitaxial processes of the UTC photodiode were optimized to augment its power endurance. Meanwhile， the responsivity of the photodiode was improved through the adoption of an integrated back-illuminated lens complemented by the addition of a metallic reflective layer. By establishing a precise model of the photodiode， we have refined the bandwidth characteristic of the photoreceiver using impedance compensation and broadband matching circuit design techniques. Flip-chip bonding the photodiode chip onto the microwave integrated circuit chip has substantially mitigated the impact of interconnect circuits on high-frequency performance. Furthermore， the thermal conductivity and high-power resilience of the detector chip were enhanced via gold-tin alloy micro-bump interconnections and the design of a high thermal conductivity substrate layer. The three-dimensional heterogeneous integrated photoreceiver features a 1-dB bandwidth of 42 GHz， an RF return loss exceeding 11 dB， a responsivity surpassing 0.85 A/W， a dark current below 50 nA， and a saturated input optical power of over 120 mW.By leveraging the distinctive properties of the UTC-PD， our three-dimensional （3D） heterogeneous integrated photoreceiver design achieves superior efficiency and responsiveness， positioning it as a leading solution for cutting-edge microwave photonics applications.
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SHANG Jia-Le, CHEN Yan, YAN Hao-Ran, DI Yun-Xiang, HUANG Xin-Ning, LIN Tie, MENG Xiang-Jian, WANG Xu-Dong, CHU Jun-Hao, WANG Jian-Lu
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
In the realm of optoelectronics， photodetectors play pivotal roles， with applications spanning from high-speed data communication to precise environmental sensing. Despite the advancements， conventional photodetectors grapple with challenges with response speed and dark current. In this study， we present a photodetector based on a lateral MoTe2 p-n junction， defined by a semi-floating ferroelectric gate. The strong ferroelectric fields and the depletion region of the p-n junction in the device are notably compact， which diminish the carrier transit time， thereby enhancing the speed of the photoelectric response. The non-volatile MoTe2 homojunction， under the influence of external gate voltage pulses， can alter the orientation of the intrinsic electric field within the junction. As a photovoltaic detector， it achieves an ultra-low dark current of 20 pA， and a fast photo response of 2 μs. The spectral response is extended to the shortwave infrared range at 1550 nm. Furthermore， a logic computing system with light/no light as binary input is designed to convert the current signal to the voltage output. This research not only underscores the versatility of 2D materials in the realm of sophisticated photodetector design but also heralds new avenues for their application in energy-efficient， high-performance optoelectronic devices.
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LIN Chang-Qing, ZHOU Shuang-Xi, LI Lu-Fang, LIU Gao-Rui, SUN Hai-Bin, ZHANG Yu, LIN Jia-Mu, SUN Sheng-Li
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
With the development of remote sensing technology， the detection sensitivity of infrared system is increasingly required. The infrared imaging detection technology based on linear avalanche device can effectively improve the detection sensitivity in high frame frequency applications. Based on the short-wave infrared linear avalanche detector assembly of 512×512， a small-aperture and lightweight infrared imaging system is designed and its performance is tested under low reverse bias. The test results show that the increase of SNR of the imaging system based on the linear avalanche infrared detector is basically linear with the multiplication factor M under short integration time， and the SNR of the system is 3 times that of the traditional camera of the same caliber.
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QIU Qian-li, ZHANG Jin-guo, ZHOU Dong-jie, TAN Chong, SUN Yan, HAO Jia-ming, DAI Ning
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Dual-band thermal emitters with narrow bandwidths are important in various applications in the infrared field， such as in infrared sensing and infrared imaging. However， conditions for narrowband emission in different wavelengths can conflict with each other， making it difficult to achieve dual-band emitter. In this paper， a new type of lithography-free infrared dual-band thermal emitter is proposed， which consists of alternately deposited Ge and YbF3 films on Al films. The narrowband emission characteristics stem from the Tamm plasmon polaritons （TPP） that can be excited by the distributed Bragg reflector and the Al substrate under certain conditions. The geometric parameters are optimized using multi-objective particle swarm optimization. The experiment results confirm that dual-band emitter can simultaneously exhibit narrowband emitter characteristics in both mid-wave infrared （MWIR） and long-wave infrared （LWIR） regions. The proposed method can be used in the design of multi-band emitssion modulation applications， which can be applied in the fields of multi-gas sensing and multi-band infrared camouflage.
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GONG Hang, ZHOU Fu-Gui, FENG Ruize, FENG Zhi-Yu, LIU Tong, SHI Jing-Yuan, SU Yong-Bo, JIN Zhi
DOI:
Abstract:
In this work， we investigate the impact of the whole small recess offset on DC and RF characteristics of InP high electron mobility transistors （HEMTs）. Lg = 80 nm HEMTs are fabricated with a double-recessed gate process. We focus on their DC and RF responses， including the maximum transconductance （gm_max）， ON-resistance （RON）， current-gain cutoff frequency （fT）， and maximum oscillation frequency （fmax）. The devices have almost same RON. The gm_max improves as the whole small recess moves toward the source. However， a small gate to source capacitance （Cgs） and a small drain output conductance （gds） lead to the largest fT， although the whole small gate recess moves toward the drain leads to the smaller gm_max. According to the small-signal modeling， the device with the whole small recess toward drain exhibits an excellent RF characteristics， such as fT = 372 GHz and fmax = 394 GHz. This result is achieved by paying attention to adjust resistive and capacitive parasitics， which play a key role in high-frequency response.
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LI Xiang, HU Jin-Han, ZHONG Zhi-Peng, CHEN Yu-Zhong, WANG Zhi-Qiang, SONG Miao-Miao, WANG Yang, ZHANG Lei, LI Jian-Feng, HUANG Hai
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation， low cost， lightweight， and flexibility. In this work， we explored the application of the organic semiconductor Y6-1O single crystal in photodetection devices. Firstly， Y6-1O single crystal material was prepared on a silicon substrate using solution droplet casting method. The optical properties of Y6-1O material were characterized by polarized optical microscopy， fluorescence spectroscopy， etc.， confirming its highly single crystalline performance and emission properties in the near-infrared region. Phototransistors based on Y6-1O materials with different thicknesses were then fabricated and tested. It was found that the devices exhibited good visible to near-infrared photoresponse， with the maximum photoresponse in the near-infrared region at 785 nm. The photocurrent on/off ratio reaches 102， and photoresponsivity reaches 16 mA/W. It was also found that the spectral response of the device could be regulated by gate voltage as well as the material thickness， providing important conditions for optimizing the performance of near-infrared photodetectors. This study not only demonstrates the excellent performance of organic phototransistors based on Y6-1O single crystal material in near-infrared detection but also provides new ideas and directions for the future development of infrared detectors.
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HUANG Zhen, ZHANG Yong, GONG Jin-Fu
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
In response to the scarcity of infrared aircraft samples and the tendency of traditional deep learning to overfit， a few-shot infrared aircraft classification method based on cross-correlation networks is proposed. This method combines two core modules： a simple parameter-free self-attention and cross-attention. By analyzing the self-correlation and cross-correlation between support images and query images， it achieves effective classification of infrared aircraft under few-shot conditions. The proposed cross-correlation network integrates these two modules and is trained in an end-to-end manner. The simple parameter-free self-attention is responsible for extracting the internal structure of the image while the cross-attention can calculate the cross-correlation between images further extracting and fusing the features between images. Compared with existing few-shot infrared target classification models， this model focuses on the geometric structure and thermal texture information of infrared images by modeling the semantic relevance between the features of the support set and query set， thus better attending to the target objects. Experimental results show that this method outperforms existing infrared aircraft classification methods in various classification tasks， with the highest classification accuracy improvement exceeding 3%. In addition， ablation experiments and comparative experiments also prove the effectiveness of the method.
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HUANG Xin-Ning, JIANG Teng-Teng, DI Yun-Xiang, XIE Mao-Bin, GUO Tian-Le, LIU Jing-Jing, WU Bin-Min, SHI Jing-Mei, QIN Qiang, DENG Gong-Rong, CHEN Yan, LIN Tie, SHEN Hong, MENG Xiang-Jian, WANG Xu-Dong, CHU Jun-Hao, GE Jun, WANG Jian-Lu
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Colloidal quantum dots （CQDs） are affected by the quantum confinement effect， which makes their bandgap tunable. This characteristic allows these materials to cover a broader infrared spectrum， providing a cost-effective alternative to traditional infrared detector technology. Recently， thanks to the solution processing properties of quantum dots and their ability to integrate with silicon-based readout circuits on a single chip， infrared detectors based on HgTe CQDs have shown great application prospects. However， facing the challenges of vertically stacked photovoltaic devices， such as barrier layer matching and film non-uniformity， most devices integrated with readout circuits still use a planar structure， which limits the efficiency of light absorption and the effective separation and collection of photo-generated carriers. Here， by synthesizing high-quality HgTe CQDs and precisely controlling the interface quality， we have successfully fabricated a photovoltaic detector based on HgTe and ZnO QDs. At a working temperature of 80 K， this detector achieved a low dark current of 5.23×10-9 A cm-2， a high rectification ratio， and satisfactory detection sensitivity. This work paves a new way for the vertical integration of HgTe CQDs on silicon-based readout circuits， demonstrating their great potential in the field of high-performance infrared detection.
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ZHANG Lei, WANG Tian-Qi, FAN Yan-Ping
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
In sub nanometer carbon nanotubes， water exhibits unique dynamic characteristics， and in the high-frequency region of the infrared spectrum， where the stretching vibrations of the internal oxygen-hydrogen （O-H） bonds are closely related to the hydrogen bonds （H-bonds） network between water molecules. Therefore， it is crucial to analyze the relationship between these two aspects. In this paper， the infrared spectrum and motion characteristics of the stretching vibrations of the O-H bonds in one-dimensional confined water （1DCW） and bulk water （BW） in （6， 6） single-walled carbon nanotubes （SWNT） are studied by molecular dynamics simulations. The results show that the stretching vibrations of the two O-H bonds in 1DCW exhibit different frequencies in the infrared spectrum， while the O-H bonds in BW display two identical main frequency peaks. Further analysis using the spring oscillator model reveals that the difference in the stretching amplitude of the O-H bonds is the main factor causing the change in vibration frequency， where an increase in stretching amplitude leads to a decrease in spring stiffness and， consequently， a lower vibration frequency. A more in-depth study found that the interaction of H-bonds between water molecules is the fundamental cause of the increased stretching amplitude and decreased vibration frequency of the O-H bonds. Finally， by analyzing the motion trajectory of the H atoms， the dynamic differences between 1DCW and BW are clearly revealed. These findings provide a new perspective for understanding the behavior of water molecules at the nanoscale and are of significant importance in advancing the development of infrared spectroscopy detection technology.
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TIAN Yu, YU Chun-Lei, LI Xue, SHAO Xiu-Mei, LI Tao, YANG Bo, YU Xiao-Yuan, CAO Jia-Shen, GONG Hai-Mei
DOI: 10.11972/j.issn.1001-9014.2024.06.005
Abstract:
The pursuit of ultra-small pixel pitch InGaAs detectors necessitates a meticulous approach to addressing challenges associated with crosstalk reduction and dark current minimization. By developing the fabrication process technology of micro-mesa InGaAs detector， a test structure featuring a micro-mesa InGaAs photosensitive chip with 10 μm and 5 μm pixel pitch was successfully prepared. Subsequently， a comprehensive investigation was conducted to analyze the impact of the micro-mesa structure on crosstalk and dark current characteristics of the InGaAs detector. The obtained results revealed the efficacy of the micro-mesa structure in effectively suppressing crosstalk between adjacent pixels when the isolation trench etches into the absorption layer. However， a noteworthy challenge emerged as the fabrication processes induced material damage， leading to a considerable increase in recombination current and Ohmic leakage current. This adverse effect， in turn， manifested as a dark current escalation by more than one order of magnitude. The significance of these findings offers a novel perspective for the manufacturing of ultra-small pixel pitch InGaAs focal plane detectors.
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SHI Ce, XIE Mao-Bin, ZHENG Wei-Bo, JI Ruo-Nan, WANG Shao-Wei, LU Wei
DOI: 10.11972/j.issn.1001-9014.2024.06.012
Abstract:
This work introduces a novel method for measuring thin film thickness， employing a multi-wavelength method that significantly reduces the need for broad-spectrum data. Unlike traditional techniques that require several hundred spectral data points， the multi-wavelength method achieves precise thickness measurements with data from only 10 wavelengths. This innovation not only simplifies the process of spectral measurement analysis but also enables accurate real-time thickness measurement on industrial coating production lines. The method effectively reconstructs and fits the visible spectrum （400~800 nm） using a minimal amount of data， while maintaining measurement error within 7.1%. This advancement lays the foundation for more practical and efficient thin film thickness determination techniques in various industrial applications.
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WANG Zhen-Hua, YANG Wu-Zhong, LIU Xiang-Feng, WANG Feng- Xiang, XU Wei-Ming, SHU Rong
DOI: 10.11972/j.issn.1001-9014.2024.06.015
Abstract:
With a single-photon detector， photon-counting LiDAR （PCL） captures a large amount of background noise along with the target scattered/reflected echo signals， because of the influence of factors such as the background environment， target characteristics， and instrument performance. To accurately extract the signal photons on the ground surface from a noisy photon point cloud （PPC）， this paper presents an adaptive denoising approach for PPC using two levels of voxels. First， coarse denoising is performed utilizing large-scale voxels， which are built based on the spatial distribution features of the PPC. The density of the voxel is then used to select the voxels that contained dense signal photons. Second， fine denoising with small-scale voxels is conducted. These voxels are built using the nearest neighbor distance， and a topologicalrelationship between voxels is used to further extract voxels containing signal photons aggregated on the ground surface. Finally， this method is performed on the PPC from ATL03 datasets collected by the Ice， Cloud， and Land Elevation Satellite-2 both during daytime and at night and compared with the improved Density-Based Spatial Clustering of Applications with Noise （DBSCAN）， improved Ordering Points to Identify the Clustering Structure （OPTICS）， and the method used in the ATL08 datasets. The results show that the proposed method has the best performance， with precision， recall， and F1 score of 0.98， 0.97， and 0.98， respectively.
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DOI: 10.11972/j.issn.1001-9014.2024.06.009
Abstract:
Aiming to address the issue of high complexity in estimating the parameters of the attributed scattering center model （ASCM） in synthetic aperture radar （SAR） images， a sparse representation parameter estimation method that integrates information from the image domain is proposed. Firstly， the improved watershed algorithm is used to segment the scattering centers of different regions. Subsequently， based on the segmentation results， the frequency domain sparse representation dictionary is decoupled and applied in a serialized manner for scattering center parameter estimation using orthogonal matching pursuit to reduce algorithm complexity. Based on simulated data and measured MSTAR data， the effectiveness and efficiency of the proposed parameter extraction method were validated， and the optimization of theoretical complexity was analyzed. The results indicate that this method can significantly reduce the time and space complexity of the algorithm while achieving results close to those of the conventional orthogonal matching pursuit algorithm. The proposed method can be used for the efficient extraction of scattering center parameters in SAR images.
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LV Wen-Hao, FANG Fu-Ping, TIAN Yuan-Rong
DOI: 10.11972/j.issn.1001-9014.2024.06.008
Abstract:
Synthetic aperture radar （SAR） is a high-resolution two-dimensional imaging radar， however， during the imaging process， SAR is susceptible to intentional and unintentional interference， with radio frequency interference （RFI） being the most common type， leading to a severe degradation in image quality. To address the above problem， numerous algorithms have been proposed. Although inpainting networks have achieved excellent results， their generalization is unclear， and whether they still work effectively in cross-sensor experiments needs further verification. Through time-frequency analysis to interference signals， this work finds that interference holds domain invariant features between different sensors. Therefore， this work reconstructs the loss function and extracts the domain invariant features to improve its generalization. Ultimately， this work proposes a SAR RFI suppression method based on domain invariant features， and embeds the RFI suppression into SAR imaging process. Compared to traditional notch filtering methods， the proposed approach not only removes interference but also effectively preserves strong scattering targets. Compared to PISNet， our method can extract domain invariant features and holds better generalization ability， and even in the cross-sensor experiments， our method can still achieve excellent results. In cross-sensor experiments， training data and testing data come from different radar platforms with different parameters， so cross-sensor experiments can provide evidence for the generalization.
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YANG Yong-Kang, GUO Hong-Jie, CHEN Wen-Bin, QU Bai-Ang, YU Zhi-Guo, TAN Man-Qing, GUO Wen-Tao, LIU Hai-Feng
DOI: 10.11972/j.issn.1001-9014.2024.06.014
Abstract:
This article introduces a method of achieving high polarization extinction ratio using a subwavelength grating structure on a lithium niobate thin film platform， and the chip is formed on the surface of the lithium niobate thin film. The chip， with a length of just 20 μm， achieved a measured polarization extinction ratio of 29 dB at 1 550 nm wavelength. This progress not only proves the possibility of achieving a high extinction ratio on a lithium niobate thin film platform， but also offers important technical references for future work on polarization beam splitters， integrated fiber optic gyroscopes， and soon.
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ZHANG Meng, YANG Xi, GUO Jia-Wei, CAI He, WU Xin-Yang, HAN Ju-Hong, WANG Shun-Yan, WANG You
DOI: 10.11972/j.issn.1001-9014.2024.06.013
Abstract:
An LD directly-pumped solid-state laser is considered to be one of the most promising mid-infrared light sources because of its simple principle， small size， and compact structure for the generation of mid-infrared （MIR） lasers in the 3~5 μm band. However， the quantum defect of LD directly-pumped MIR solid-state lasers will be much larger than that of ordinary near-infrared LD pumped solid-state lasers， which may lead to thermal damage and limit their development. In order to solve this problem， the methods of reducing the specific surface area of the crystal and improving the thermal energy released by the crystal structure are discussed， and the optimal length of the laser crystal is determined. The cooling structures of barium yttrium fluoride laser crystals （Ho3+：BY2F8） of different lengths were studied by thermal simulation using COMSOL software. The experimental results show that the output power can be increased and the thermal stress in the laser crystal can be alleviated by using the laser crystal whose length is slightly shorter than that of the cooler. The final experiment shows that when the pump repetition rate is 15 Hz and the pulse width is 90 μs， the single pulse energy is 7.28 mJ at the output wavelength of 3.9 μm， which is about 3 times as large as that of the crystal with the length of 10 mm （2.81 mJ）. Such results should be another breakthrough of our team since the first directly-pumped solid-state MIR laser was realized more than a year ago. It might pave the way for the construction of a feasible MIR laser in the near future.
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YU Peng, TIAN Xiao-Jian, QI Nan, PIAO Yan
DOI: 10.11972/j.issn.1001-9014.2024.06.018
Abstract:
Person re-identification is the task of retrieving a specified target from multiple data sources. The difference between infrared （IR） and visible light （VIS） images is large， and cross-modal retrieval of visible light and infrared images is one of the main challenges. In order to have the same retrieval ability even in low light or at night， the judgment needs to be achieved by combining cross-modal modeling of infrared images. In this paper， we propose a new method of guiding attention through human keypoints， where global features are split into local features by keypoint guidance， and then the original model is retrained with the generated local masks to strengthen the attention to different local information. Using this method， the model can better understand and utilize the key regions in the image， thus improving the accuracy of the person re-identification task.
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Zhang Xing-Yu, Zhu Shou-Zheng, Zhou Tian-Shu, Qi Hong-Xing, Wang Jian-Yu, Li Chun-Lai, Liu Shi-Jie
DOI: 10.11972/j.issn.1001-9014.2024.06.016
Abstract:
The encoding aperture snapshot spectral imaging system， based on compressive sensing theory， can be regarded as an encoder， which can efficiently obtain compressed two-dimensional spectral data and then decode it into three-dimensional spectral data through deep neural networks. However， training the deep neural networks requires a large amount of clean data that is difficult to obtain. To address the problem of insufficient training data for deep neural networks， a self-supervised hyperspectral denoising neural network based on neighborhood sampling is proposed. This network is integrated into a deep plug-and-play framework to achieve self -supervised spectral reconstruction. The study also examines the impact of different noise degradation models on the final reconstruction quality. Experimental results demonstrate that self-supervised learning method enhances the average peak signal-to-noise ratio by 1.18 dB and improves the structural similarity by 0.009 compared with the supervised learning method. Additionally， it achieves better visual reconstruction results.
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LI Xue-Nan, ZHAO Zeng-Yue, YU Fei-Long, CHEN Jin, LI Guan-Hai, LI Zhi-Feng, CHEN Xiao-Shuang
DOI: 10.11972/j.issn.1001-9014.2024.06.011
Abstract:
Metasurfaces provide a potent platform for the dynamic manipulation of electromagnetic waves. Coupled with phase-change materials， they facilitate the creation of versatile metadevices， showcasing various tunable functions based on the transition between amorphous and crystalline states. However， the inherent limitation in tunable states imposes constraints on the multiplexing channels of metadevices. Here， this paper introduces a novel approach - a multi-functional metadevice achieved through the two-level control of the encoding phase-change metaatoms. Utilizing the phase-change material Ge2Sb2Se4Te1 （GSST） and high refractive-index liquid diiodomethane （CH2I2）， this paper showcases precise control over electromagnetic wave manipulation. The GSST state governs the tunable function， switching it ON and OFF， while the presence of liquid in the hole dictates the deflection angle when the tunable function is active. Importantly， our tunable coding metasurface exhibits robust performance across a broad wavelength spectrum. The incorporation of high refractive-index liquid extends the regulatory dimension of the metadevice， enabling dynamic switching of encoding bit levels. This two-level tunable metadevice， rooted in phase-change materials， presents a promising avenue for the dynamic control of functions.
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CHEN Yan, MENG Fan-Zhong, XUE Hao-Dong, ZHANG Ao, GAO Jianjun
DOI: 10.11972/j.issn.1001-9014.2024.06.007
Abstract:
Based on the GaAs planar Schottky diode process， a W band wideband frequency tripler MMIC is designed with a reverse parallel diode pair. By combining the finite element method and equivalent circuit method， an accurate equivalent circuit model of the planar Schottky diode is built in the frequency range of 10~280 GHz. The nonlinear harmonic balance tool is utilized to achieve the optimal frequency tripler design in the W band. The measurement results show that the frequency multiplication loss is less than 15 dB under 17 dBm driving power， and efficiency up to 6.7%. The chip size is 0.80 mm×0.65 mm×0.05 mm．
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HABIBA Um E, Chen Tian-Ye, Liu Chi-Xian, Dou Wei, Liu Xiao-Yan, Ling Jing-Wei, Pan Chang-Yi, Wang Peng, Deng Hui-Yong, Shen Hong, Dai Ning
DOI: 10.11972/j.issn.1001-9014.2024.06.004
Abstract:
The response wavelength of the blocked-impurity-band （BIB） structured infrared detector can reach 200 μm， which is the most important very long wavelength infrared astronomical detector. The ion implantation method greatly simplifies the fabrication process of the device， but it is easy to cause lattice damage， introduce crystalline defects， and lead to the increase of the dark current of detectors. Herein， the boron-doped germanium ion implantation process was studied， and the involved lattice damage mechanism was discussed. Experimental conditions involved using 80 keV energy for boron ion implantation， with doses ranging from 1
1013 to 3 1015 cm-2. After implantation， thermal annealing at 450 °C was implemented to optimize dopant activation and mitigate the effects of ion implantation. Various sophisticated characterization techniques， including X-ray diffraction （XRD）， Raman spectroscopy， X-ray photoelectron spectroscopy （XPS）， and secondary ion mass spectrometry （SIMS） were used to clarify lattice damage. At lower doses， no notable structural alterations were observed. However， as the dosage increased， specific micro distortions became apparent， which could be attributed to point defects and residual strain. The created lattice damage was recovered by thermal treatment， however， an irreversible strain induced by implantation still existed at the high doses. - 1
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Luan Yi-Fei, Wang Xiang, Gu Luo, Lin Yue, Yang Qiu-Jie, He Zhi-Ping
DOI: 10.11972/j.issn.1001-9014.2024.06.010
Abstract:
As a key parameter for characterizing the radiation characteristics of objects， emissivity has significant value in accurate measurement for high-temperature target identification， material modification， and regulation of metal smelting process. The multispectral radiation method for measuring emissivity has become a research hotspot due to its non-contact and fast measurement speed advantages， and its measurement accuracy is determined by the solution accuracy of the underdetermined equation system. At present， the research on the solution accuracy of the underdetermined system of equations mainly focuses on the error of the equation solving algorithm， ignoring the measurement error of the spectrometer itself， which leads to the failure of controlling the system error in a reasonable way. In this paper， based on the assumption of retardation with wide application range and high measurement accuracy， the influence of the number of spectral channels and signal-to-noise ratio on the emissivity measurement error under different conditions is simulated. The parameter configurations of the spectrometer under the corresponding conditions are determined and the effect of emissivity measurement is experimentally verified. The experimental results show that， using the multispectral radiation method based on the slow-change assumption， the number of spectral channels of the spectrometer should be not less than 400 and the signal-to-noise ratio should not be less than 1000 in order to make the blackbody emissivity measurement error less than 1%. For the targets with complex emissivity changes， the spectrometer should have at least 1 000 spectral channels and signal-to-noise ratios of more than 1 200 in order to make the measurement error less than 1%. Taking into account the matching relationship between algorithm errors and spectrometer parameters is the key to effectively controlling system errors and obtaining more accurate emissivity measurement results. This provides a new basis and solution for the precise measurement of emissivity using multispectral radiation methods， which is of great significance for the accurate identification of high-temperature targets and related applications.
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QIN Jia-Yi, LUO Man, CHENG Tian-Tian, MENG Yu-Xin, ZU Yuan-Ze, WANG Xin, YU Chen-Hui
DOI: 10.11972/j.issn.1001-9014.2024.06.003
Abstract:
Hexagonal boron nitride （h-BN） is found to have widespread application， owing to its outstanding properties， including gate dielectrics， passivation layers， and tunneling layers. The current studies on the fundamental physical properties of these ultrathin h-BN films and the electron tunneling effect among them are inadequate. In this work， the effective mass in h-BN was successfully determined through a combined approach of experimental and theoretical research methods by fitting the current-voltage curves of metal/insulator/metal structures. It was observed that within a range of 4~22 layers， the effective mass of h-BN exhibits a monotonic decrease with an increase in the number of layers. Precisely ascertain the physical parameters of the Fowler-Nordheim tunneling model in the context of electron tunneling in h-BN by utilizing the extracted effective mass. Additionally， the impact of fixed charges at the metal/h-BN interface and various metal electrode types on Fowler-Nordheim tunneling within this structure was investigated utilizing this physical parameter in Sentaurus TCAD software. This work is informative and instructive in promoting applications in the fields of h-BN related infrared physics and technology.
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ZHAO Zhen-Yu, Hideaki Kitahara, ZHANG Chen-Hao, Masahiko Tani
DOI: 10.11972/j.issn.1001-9014.2024.06.001
Abstract:
An enhancement of mid-wavelength infrared absorbance is achieved via a cost-effectively chemical method to bend the flakes by grafting two types of alkane octane （C8H18） and dodecane （C12H26） onto the surface terminals respectively. The chain-length of alkane exceeds the bond-length of surface functionalities Tx （=O，-OH，-F） so as to introduce intra-flake and inter-flake strains into Ti3C2Tx MXene. The electronic microscopy （TEM/AFM） shows obvious edge-fold and tensile/compressive deformation of flake. The alkane termination increases the intrinsic absorbance of Ti3C2Tx MXene from no more than 50% down to more than 99% in the mid-wavelength infrared region from 2.5 μm to 4.5 μm. Such an absorption enhancement attribute to the reduce of infrared reflectance of Ti3C2Tx MXene. The C-H bond skeleton vibration covers the aforementioned region and partially reduce the surface reflectance. Meanwhile， the flake deformation owing to edge-fold and tensile/compression increase the specific surface area so as to increase the absorption as well. These results have applicable value in the area of mid-infrared camouflage.
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ZHAO Ji-Cong, DANG Yan-Meng, HOU Hai-Yang, LIN Ye-Fan, SUN Hai-Yan, ZHANG Kun
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
In this paper， we propose an RLC equivalent circuit model theory which can accurately predict the spectral response and resonance characteristics of metamaterial absorption structures， extend its design， and characterize the parameters of the model in detail. By employing this model， we conducted computations to characterize the response wavelength and bandwidth of variously sized metamaterial absorbers. A comparative analysis with Finite Difference Time Domain （FDTD） simulations demonstrated a remarkable level of consistency in the results. The designed absorbers were fabricated using micro-nano fabrication processes， and were experimentally tested to demonstrate absorption rates exceeding 90% at a wavelength of 9.28 μm. The predicted results are then compared with test results. The comparison reveals good consistency in two aspects of the resonance responses， thereby confirming the rationality and accuracy of this model.
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BAI Zhi-Zhong, HUANG Ming, Xu Zhi-Cheng, ZHOU Yi, ZHU Yi Hong, SHEN Yi-Ming, ZHANG Jun-Lin, CHEN Hong-Lei, DING Rui-Jun, CHEN Jian-Xin
DOI: 10.11972/j.issn.1001-9014.2024.06.002
Abstract:
In this paper， the research results of 12.5 μm long-wavelength infrared InAs/GaSb superlattice focal plane arrays were reported. The superlattice structure was grown on GaSb substrate using molecular beam epitaxy （MBE） technology. The respective structure of absorption region is 15ML （ InAs） /7ML （ GaSb）. The detector adopts PBπBN double barrier structure to suppress the dark current. A long-wave focal plane detector with the size of 1 024×1 024 and the pixel center-to-center distance of 18 μm was developed. The detector is packaged by a metal dewar， and a superlattice long-wavelength detector cryocooler assembly is formed by coupling with a refrigerator. At 60 K measurement， the detector has 50% cut-off wavelength of 12.5 μm. The detector has a peak detectivity of 6.6×1010 cm?Hz1/2/W ， dead pixels rate of 1.05% and a noise equivalent temperature difference （NETD） is 21.2 mK. The Infrared images of the test have been taken clearly using the infrared imaging detector.
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Dong Chengang, Shi Wei, Han Xiaowei, Wang Zhiquan, Wang Xin, Zhang Xiuxing
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
As an important emitter of terahertz radiation, the traditional antenna has limited flexibility due to its fixed polarization state. In response to this issue, we have designed and studied a polarization-adjustable four-element terahertz gallium arsenide photoconductive antenna array, aiming to enhance its versatility and applicability in various applications. By precisely controlling the excitation of each element, the antenna array can achieve precise control of linearly and circularly polarized terahertz waves through in-phase unequal amplitude excitation and phase difference excitation. The results show that with in-phase unequal amplitude excitation, flexible control of linearly polarized terahertz waves within a 360-degree range can be achieved. With a 90-degree phase difference excitation, circularly polarized terahertz waves are generated, with a -10 dB impedance bandwidth range of 0.057 THz to 1.013 THz and a relative bandwidth of 178.69%. The axial ratio bandwidth range is 0.815 THz to 0.947 THz, with a relative bandwidth of 14.98%.
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Yang Lifeng, Feng Yanqing, WangJianyu
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
To address the issues of low detection rate and high false alarm rate caused by complex background during sub-pixel aerial aircraft detection in hyperspectral remote sensing image, an aerial aircraft detection method was proposed based on contrails cloud proposal. Firstly, a hyperspectral semantic segmentation model was used to search for the contrails cloud, and ROIs of aircraft were proposed to reduce invalid search ranges and suppress false alarms based on the contrails cloud; Secondly, an endmember extraction algorithm based on dictionary learning and semi-blind non-negative matrix factorization was proposed to improve the accuracy of aircraft endmember extraction for hyperspectral subpixels; Finally, verification experiments were carried out on the hyperspectral remote sensing image dataset of gaofen-5 satellite, and the results demonstrated that the algorithm proposed in this paper can effectively suppress false alarms in complex scenes, and significantly improve the detection rate and detection accuracy of sub-pixel aerial vehicles.
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SUN Bin, XIA Xing-Ling, FU Rong-Guo, SHI Liang
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Aiming at the problem that infrared small target detection faces low contrast between the background and the target and insufficient noise suppression ability under the complex cloud background, an infrared small target detection method based on the tensor nuclear norm and direction residual weighting is proposed. Based on converting the infrared image into an infrared patch tensor model, from the perspective of the low-rank nature of the background tensor, and taking advantage of the difference in contrast between the background and the target in different directions, we design a double-neighborhood local contrast based on direction residual weighting method (DNLCDRW) combined with the partial sum of tensor nuclear norm (PSTNN) to achieve effective background suppression and recovery of infrared small targets. Experiments show that the algorithm is effective in suppressing the background and improving the detection ability of the target.
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HUANG Shan-Jie, ZHAO Jin-Song, WANG Ling-Xue, SONG Teng-Fei, XU Fang-Yu, CAI Yi
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Smooth objects such as metals， optical mirrors， and silicon wafers generally have extremely low emissivity and high reflectivity， and are called low emissivity objects.The extremely weak radiation from low emissivity objects will be submerged by the environmental radiation reflected from their surface. Infrared temperature measurement of low emissivity objects has always been a challenge in the field of infrared temperature measurement. Due to the continuously growing demand for non-contact temperature measurement of low emissivity objects in fields such as metal smelting， solar telescope thermal control， and semiconductor production， a large number of infrared temperature measurement methods for low emissivity objects have been proposed. First， this paper elaborates on the difficulties of the infrared temperature measurement of low emissivity objects and summarizes the temperature measurement methods currently used for low emissivity objects into five categories. Then， the basic principles and technical routes of each temperature measurement method were summarized， and the advantages and disadvantages of each temperature measurement method were analyzed in detail. Finally， the possible development directions of temperature measurement for low emissivity objects were discussed.
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LI Yifan, YANG He, YANG Rui, JIA Yiming, HU Jiamin, LOU Cunguang, YUYu, LIU X iuling, YAO Jianquan
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Due to its distinctive traits such as low energy consumption， high transmittance， potent anti-interference capacity， fingerprint， THZ flexible regulation assumes a crucial role in detection， imaging， radar， and military defense， and has garnered significant attention from scholars both domestically and internationally in recent years. Nevertheless， high costs and losses remain significant factors restricting the advancement of terahertz regulation. Perovskite materials possess outstanding photoelectric properties， a straightforward preparation process， the capacity for mass production， and thereby become one of the most promising materials for the fabrication of terahertz detectors. Additionally， the facile tunability of perovskite compensates for the difficulty in adjusting the metasurface and meets the requirement for tunable metasurface. The combination of the two enables effective regulation of terahertz in the light field. In this paper， we have designed two types of coded metasurface composed of organic-inorganic hybrid perovskite CH3NH3PbI3， polyimide， and aluminum， and manipulated the operating frequencies of the two structures through light field control. The results were compared with theoretical calculations to verify the effect. The first structure can be controlled by the light field to select between a broadband operating frequency and high efficiency. The second structure functions only at 0.1THz and can vary the phase through light， thereby reversing the phase of the original structure to control the direction of beam reflection. On this basis， we fabricated the device and verified it. To a certain extent， this paper fills the void in the field of optical field regulation of coded metasurface and offers a train of thought for subsequent research.
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MEI Xue-Han, CHEN Xiang, XU Gang, YANG Yuan-Zhong, ZHANG Zhong, LEI Cheng, LI Sheng, WANG Xing-Huan, WANG Du
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Lasers near the wavelength of 2 μm are located in the atmospheric transmission window and the strong absorption peak of water， and have important applications in medicine， LIDAR， material processing， and as pump sources for mid-infrared lasers. The thulium-doped fiber laser （TDFL） stands out as a critical light source capable of delivering high power outputs at this wavelength. In this paper， to address the problems of relaxation oscillation and inter-modal four-wave mixing in quasi-continuous wave （QCW） TDFL， the time and frequency-domain output characteristics of the laser are optimized by increasing the bias current， optimizing the length of the gain fiber， and changing the diameter of the fiber coiling， etc. The effects of different gain fiber structures on the fiber transmission modes are also investigated. The developed QCW-TDFL achieves a peak power of 894 W and an average power of 89.4 W at a central wavelength of 1939.2 nm with a pulse width of 100 μs， a repetition frequency of 1 kHz and a duty cycle of 10%， and obtains stable and controllable pulse output waveforms and spectral characteristics.
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Li Zhaoxu, Xu Qingyu, An Wei, He Xu, Guo Gaowei, Li Miao, Ling Qiang, Wang Longguang, Xiao Chao, Lin Zaiping
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
Small target detection has been a classic research topic in the field of infrared image processing, and the objects are usually brighter than the local background. However, in some scenarios, the target brightness may be lower than the background brightness. For example, the civil airplanes usually have low-temperature skin when cruising, appearing as dark points on medium spatial resolution thermal infrared satellite images. There are few features of these objects, so the current detection networks are redundant. Hence, authors proposed a lightweight dark object detection network, AirFormer. It only has 37.1K parameters and 46.2M floating-point operations on a 256×256 image. Considering the lack of infrared dark object detection dataset, authors analyzed the characteristics of airplanes on thermal infrared satellite images, and then developed a simulated flying aircraft detection dataset called IRAir. AirFormer achieves 71.0% at recall and 82.6% at detection precision on the IRAir dataset. In addition, after training on simulated data, AirFormer has achieved detection of real flying airplanes on the thermal infrared satellite images.
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Yang Lifeng, Chen Zhuo, Chen Fansheng, WangJianyu
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
The acquisition of aircraft altitude information is crucial for aviation safety and traffic control applications. Infrared remote sensing technology can accurately measure the thermal radiation information of targets, which means there is potential for quantitative observation of certain characteristics of aircraft target. A method for estimating the altitude of airborne targets based on infrared multi-channel feature matching is proposed in this paper. Firstly, a thermal infrared radiation characteristic observation model of aircraft is established, which based on the thermal infrared radiation characteristics of large aircraft and atmospheric radiative transfer models. Secondly, based on the observation model, a spectral database of aircraft方 at different altitudes and flight states under different atmospheric condition can be obtained by simulating. Thirdly, target spectral information can be extracted from remote sensing images and the altitude information can be estimated with using spectral angle matching (SAM). Finally, verification and analysis were completed using simulation data and SDGSAT-1 in-orbit data. The results indicate that the proposed method can achieve kilometer-level estimation accuracy for aircraft at cruising altitude. This method provides a new solution for estimating the altitude of aircraft and has important application potential.
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FU Peng, HE Dao-Gang, LIU Jun, WANG Yue-Ming
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction. In satellite laser communication systems， the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation. However， there are strong non-uniformity and blind pixels in the short-wave infrared image， which makes the image distorted and leads to the decrease of spot centroid positioning accuracy. Therefore， the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance. A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two， further model-based localization error simulations are performed， and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector. The experimental results show that the non-uniformity of the corrected image is reduced from 7% to 0.6%， the blind pixels rejection rate reaches 100%， the frame rate can be up to 2000 Hz， and the spot centroid localization accuracy is as high as 0.1 pixel point， which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.
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MA Qiu-Jing, DUAN Wei-Bo, YU Tian-Yan, LI Da-Qi, YU De-Ming, LIU Bao-Jian, ZHUANG Qiu-Hui, LIU Ding-Quan
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
The effects of calcium fluoride （CaF2） doping on the optical and physical and chemical properties of Ytterbium fluoride （YbF3） materials were studied. Pure YbF3 thin films and YbF3 thin films doped with different proportions of CaF2 were deposited by electron beam and thermal evaporation， respectively. The characteristics of single layer were measured by spectrometer， stress measurement system， X-ray Diffraction （XRD）， Atomic Force Microscope （AFM） and other measuring devices. The optical constants were fitted by the classical Lorentz oscillator model. The results show that the single-layer film with better optical and physical and chemical properties is obtained by electron beam deposition， in the condition of 1% CaF2 doping. A long-wave infrared anti-reflection multi-layer sample was designed and fabricated and its spectrum and reliability test were carried out. The results show that its transmittance in the long-wave infrared region is as high as 99%， and the reliability meets the requirements of space application.
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ZHANG Jing, YANG Zhi, ZHENG Li-Ming, ZHU Xiao-Juan, WANG Ping, YANG Lin
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
This paper discusses the influence of Sb/In ratio on the transport properties and crystal quality of the 200 nm InAsxSb1-x thin film. The Sb content of InAsxSb1-x thin film in all samples was verified by HRXRD of the symmetrical 004 reflections and asymmetrical 115 reflections. The calculation results show that the Sb component was 0.6 in the InAsxSb1-x thin film grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3, which has the highest electron mobility (28560 cm2/V·s) at 300 K. At the same time, the influence of V/III ratio on the transport properties and crystal quality of Al0.2In0.8Sb/InAsxSb1-x quantum well heterostructures also has been investigated. As a result, the Al0.2In0.8Sb/InAs0.4Sb0.6 quantum well heterostructure with a channel thickness of 30 nm grown under the conditions of Sb/In ratio of 6 and As/In ratio of 3 has a maximum electron mobility of 28300 cm2/V·s and a minimum RMS roughness of 0.68 nm. Through optimizing the growth conditions, our samples have higher electron mobility and smoother surface morphology.
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Influence of crystal temperature on femtosecond laser induced ferroelectric domain inversion process
XU Tian-Xiang, WANG Sen, LIN Jin-Yang, ZHAO Ru-Wei, XU Tie-Feng, SHENG Yan
DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001
Abstract:
The near-infrared femtosecond laser induced ferroelectric domain inversion in an important method in 3D nonlinear photonic crystal fabrication. Using structures produced by this technique， a series of attractive results have been achieved in optical frequency conversion and nonlinear wavefront shaping. At present， the reported laser induced domain inversion were all implemented at room temperature. For ferroelectric crystals， it would reach the Curie point during heating， and many characterizations such as coercive field which relate to domain inversion may change seriously. However， the effect of crystal temperature on femtosecond laser induced domain inversion is undefined. In this work， the strontium barium niobate （SrxBa1-xNbO3） ferroelectric crystal with the Curie point of about 70-80℃ depends on component proportion of Sr and Ba was used for domain inversion. Direct near-infrared femtosecond laser writing was implemented at the temperature of 25-65℃. The domain inversion condition was judged based on the second-harmonic pattern in the far field. The variation tendency of threshold laser power for domain inversion depends on temperature was tested and possible reason was predicted.
Interdisciplinary Research on Infrared Science
Infrared Physics, Materials and Devices
Infrared Optoelectronic System and Application Technology
Infrared Physics, Materials and Devices
红外物理与材料器件
Infrared Physics, Materials and Devices
Infrared Spectroscopy and Remote Sensing Technology
红外光电系统与应用技术
毫米波与太赫兹技术
Infrared Physics, Materials and Devices
Infrared Optoelectronic System and Application Technology
红外学科交叉融合研究
Interdisciplinary Research on Infrared Science
Infrared Optoelectronic System and Application Technology
Millimeter Waves and Terahertz Technology
Infrared Physics, Materials and Devices
Infrared Optoelectronic System and Application Technology
Infrared Physics, Materials and Devices
Infrared Optoelectronic System and Application Technology
Millimeter Waves and Terahertz Technology
Infrared Physics, Materials and Devices
Interdisciplinary Research on Infrared Science
Infrared Physics, Materials and Devices
红外光谱与遥感技术
红外光电系统与应用技术
红外物理与材料器件
红外光电系统与应用技术
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Research on low-power consumption, high heat dissipation efficiency terahertz quantum cascade laser
TAN Cheng, YAN Chuan-Feng, ZANG Shan-Zhi, WANG Kai, GAN Liang-Hua, CAO Chen-Tao, CHEN Bing-Qi, CHEN Hong-Tai, ZHANG Yue-Heng, FANG Yu-Long, XU Gang-Yi
Abstract:
A single-mode terahertz quantum cascade laser (THz-QCL) with a two-dimensional patch antenna array as a resonant cavity is proposed and realized. The active region of each patch antenna is sandwiched between two metal layers, exhibiting full-scale subwavelength characteristics and exciting a vertical electric quadrupole mode with low radiation loss. The inter-antenna coupling within the array effectively suppresses electromagnetic leakage in the plane, allowing for a high-quality factor and low threshold current density even with only a few antennas in the array. As a result, the laser's power consumption is reduced to 950 mW. Moreover, the discrete antenna array design provides a larger heat dissipation area compared to the heat-generating area, and with the lateral heat dissipation channels offered by the unpumped regions, the thermal resistance per unit area is as low as 5.6 mK/W/cm2. By significantly reducing power consumption and enhancing heat dissipation efficiency, the laser achieves a lasing frequency of 3.18 THz, a side-mode suppression ratio (SMSR) of 19.5dB, and a beam divergence angle of 35°× 35°. It operates continuously at 3.14 mW at 20 K, with a maximum continuous operation temperature of 90 K, notably higher than that of Fabry-Pérot cavity lasers made from the same material. This work provides a novel approach to improving the continuous operating temperature of THz-QCLs.
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An Improved Template Matching Algorithm for Infrared Cross-Target Center Positioning Based on Self-Constructed Convolution Kernels
yuandijian, XU Xin-Ke, LIU Tong, WANG Jin-Wen, DU Yu
Abstract:
Target center positioning is a critical technology in the calibration process of infrared thermal imagers. Given the relatively complex morphology of target images, we propose a center positioning algorithm based on improved template matching with self-constructed convolution kernels. The algorithm first constructs a normalized template with target image features and performs matching operations on downsampled and preprocessed target images to obtain coarse positioning results. Based on the coarse positioning center, the original image undergoes ROI fine matching, and further correction is achieved through a subpixel subdivision algorithm, ultimately determining the precise target center position. This algorithm effectively detects target images with blurring and indistinct edge features, avoiding interference from blurring, occlusion, complex backgrounds, or indistinct features. It demonstrates good robustness, accurately positions the target center, and operates at high speed. Compared to traditional template matching methods like CCORR, NCC, and Hough transform, it offers significant improvements and meets the positioning requirements in the automatic calibration process of infrared thermal imagers.
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Infrared remote sensing image super-resolution network by fusion of dense connection and multi-attention mechanism
XU Xinhao, WANG Jun, WANG Feng, Sun Shengli
Abstract:
Space-borne infrared remote sensing images have crucial application value in the fields of environmental monitoring and military reconnaissance. Nonetheless, due to limitations in technologies, atmospheric disturbances, and sensor noise, these images suffer from insufficient resolution and blurred texture details, severely restricting the accuracy of subsequent analysis and processing. To address these issues, a new super-resolution generative adversarial network model is proposed. This model integrates dense connections with the Swin Transformer architecture to achieve effective cross-layer feature transmission and contextual information utilization while enhancing the model's global feature extraction capabilities. Furthermore, we improve the traditional residual connections with multi-scale channel attention-based feature fusion, allowing the network to more flexibly integrate multi-scale features, thereby enhancing the quality and efficiency of feature fusion. A combined loss function is constructed to comprehensively optimize the performance of the generator. Comparative tests on different datasets demonstrate significant improvements with the proposed algorithm. Additionally, the super-resolved images exhibit higher performance in downstream tasks such as object detection, confirming the effectiveness and application potential of the algorithm in space-borne infrared remote sensing image super-resolution.
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Infrared UAV Detection Based on Multi-Channel Interactive Attention Mechanism and Edge Contour Enhancement
Nie Su-Zhen, CAO Jie, HAO Qun, ZHUANG Xu-Ye
Abstract:
UAVs have a wide range of applications in agriculture, logistics, rescue and disaster relief because of their compactness, lightness and flexibility. However, if they are used improperly or mismanaged, they may not only cause personal privacy leakage and property loss, but also pose a threat to public safety and even military security. Therefore, real-time and accurate detection and warning of UAVs in the airspace plays an important role. In this regard, a multi-channel interactive attention and edge contour enhancement (MCIAECE) method for infrared UAV detection is proposed. Firstly, the shallow and deep features of the infrared image are extracted by constructing a multi-channel consisting of a multi-channel interactive attention mechanism module and an edge contour enhancement module, after which the attention mechanism enhances the target features while the edge contour enhancement obtains more detailed information. Then the extracted features of each layer are fused and enhanced using the multilevel feature fusion module to obtain the detection results. The experimental results show that better results can be achieved with multi-channel interactive attention and edge contour enhancement on all three datasets. Among them, the best results are obtained on the NUDT-SIRST infrared dataset, with the detection probability and intersection and concurrency ratio of 98.83% and 85.11% respectively compared with the baseline network, and the effect is significant in the edge contour restoration of the target compared with other methods.
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Design and preparation of LWDM AWG for 1.6Tbps and above data center
HuangSong, CUI Peng-Wei, WANG Yue, WANG Liang-Liang, ZHANG Jia-Shun, MA Jun-Chi, ZHANG Chun-Xue, GUO Li-Yong, YANG Han-Ming, WU Yuan-Da, AN Jun-Ming
Abstract:
A 16-channel arrayed waveguide grating (AWG) with an 800 GHz channel spacing in the O-band has been developed and fabricated based on silica planar lightwave circuit (PLC) technology. By extending the wavelength allocation from 8 channels to 16 channels as specified in IEEE 802.3bs, we increased the number of channels and boosted transmission capacity to meet the 1.6 Tbps and higher-speed signal transmission requirements for future data centers. Through optimizing the AWG structure, it has achieved insertion loss (IL) better than -1.61 dB, loss uniformity below 0.35 dB, polarization-dependent loss (PDL) below 0.35 dB, adjacent channel crosstalk under -20.05 dB, ripple less than 0.75 dB, center wavelength offset under 0.22 nm and 1 dB bandwidth exceeding 2.88 nm. The AWG has been successfully measured to transmit 53 Gbaud 4-level pulse amplitude modulation (PAM4) signal per channel and the total transmission speed can reach 1.6Tbps and above.
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Performance analysis of electro-optic sampling detection technique with thin GaSe crystal in mid-infrared band
DU Hai-Wei, WANG Jing-Yi, LI Qiang-Shuang, SUN Chang-Ming
Abstract:
Electro-optic sampling (EOS) detection technique has been widely used in the terahertz science and technology, and it also can measure the field time waveform of the few-cycle laser pulse. Its frequency response and band limitation are determined directly by the electro-optic crystal and duration of the probe laser pulse. Here, we investigate the performance of the EOS with thin GaSe crystal in the measurement of the mid-infrared few-cycle laser pulse. The shift of the central frequency and the change of the bandwidth induced by the EOS detection are calculated, and then the pulse distortions induced in the detection process are discussed. It is found that this technique produces a red-shift of the central frequency and narrowing of the bandwidth. These changings decrease when the laser wavelength increase from 2 ?m to 10 ?m. This work can help to estimate the performance of the EOS detection technique in the mid-infrared band and offer a reference for the related experiment as well.
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Structural Design of a Wide-ridge Mid-wave Infrared Quantum Cascade Laser Based on a Supersymmetric Waveguide
DU Shu-Hao, ZHENG Xian-Tong, JIA Han, CUI Jin-Tao, ZHANG Shi-Ya, LIU Yuan, FENG Yu-Lin, LIU Ming, ZHANG Dong-Liang
Abstract:
In the process of power scaling large-area quantum cascade lasers (QCLs), challenges such as degradation of beam quality and emission of multilobe far-field modes are frequently encountered. These issues become particularly pronounced with an increase in ridge width, resulting in multimode problems. To tackle this, an innovative multiridge waveguide structure based on the principle of supersymmetry (SUSY) was proposed. This structure comprises a wider main waveguide in the center and two narrower auxiliary waveguides on either side. The high-order modes of the main waveguide are coupled with the modes of the auxiliary waveguides through mode-matching design, and the optical loss of the auxiliary waveguides suppresses these modes, thereby achieving fundamental mode lasing of the wider main waveguide. This paper employs the finite difference eigenmode (FDE) method to perform detailed structural modelling and simulation optimization of the 4.6 μm wavelength quantum cascade laser, successfully achieving a single transverse mode QCL with a ridge width of 10 μm. In comparison to the traditional single-mode QCL(with a ridge width at about 5 μm), the MRW structure has the potential to increase the gain area of the laser by 100%. This offers a novel design concept and methodology for enhancing the single-mode luminous power of mid-infrared quantum cascade lasers, which is of considerable significance.
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Research on the Punch-through Phenomenon of Separate Absorption, Charge, and Multiplication Avalanche Photodetectors
LI Chong, MA Zi-Yi, YANG Shuai, LIU Yue-Wen, WANG Jia-Xuan, LIU Yun-Fei, DONG Yu-Sen, LI Zi-Qian, LIU Dian-Bo
Abstract:
In this paper, the punch-through phenomenon was studied, based on a fabricated separate absorption, charge, and multiplication avalanche photodetector (SACM APD). The spectral response, capacitance characteristics, and I-V characteristics at different operating temperatures of the APD were measured and analyzed. Meanwhile, the device performance before and after the punch-through phenomenon were compared, and the model of the electric field region formed by external voltage was analyzed, based on the measurement results and the simulated the electric field and energy band distributions by the SILVACO. When the ion implantation energy of the charge layer was 580keV, the simulated device has a punch-through voltage of -30V and a capacitance reduction of one-third before punch-through. Then a Si SACM APD was prepared based on CMOS process. The punch-through voltage of the device was -30V and the capacitance was reduced to 1/3@1MHz before punch-through, which exactly match the simulation results. Moreover, the photocurrent after punch-through increases to 2.18 times of the before value at 808nm. The peak responsivity increases from 0.171A/W@590nm to 0.377A/W@820nm.
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Study on Correlation of Thermal Model to in-Orbit Data for Infrared Optical Payloads on FY-3E/HIRAS-II
LI Yu-Han, YANG Bao-Yu, ZHANG Qiang, GUO Zhi-Peng, WU Yi-Nong, TANG Xiao, LI Shang-Ju
Abstract:
The Infrared Hyperspectral Atmospheric Sounder II (HIRAS-II) is the key equipment on Funyun-3E (FY-3E) satellite, which can realize vertical atmospheric detection, featuring hyper spectral, high sensitivity and high precision. To ensure its accuracy of detection, it is necessary to correlate their thermal models to in-orbit data. In this work, an investigation of intelligent correlation method named Intelligent Correlation Platform for Thermal Model (ICP-TM) was established, the advanced Kriging surrogate model and efficient adaptive region optimization algorithm were introduced. After correlation with this method for FY-3E/HIRAS-II, the results indicate that compared with the data in orbit, the error of the thermal model has decreased from 5 K to within ±1 K in cold case (10℃). Then the correlated model is validated in hot case (20℃), and the correlated model exhibits good universality. This correlation precision is also much superior to the general ones like 3 K in other similar literatures. Furthermore, the process is finished in 8 days using ICP-TM, the efficiency is much better than 3 months based on manual. The results show that the proposed approach significantly enhances the accuracy and efficiency of thermal model, this contributes to the precise thermal control of subsequent infrared optical payloads.
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Multi-physics coupling-based multi-parameter joint optimization technique for aerial target infrared detection
Abstract:
One of the key areas of advancement in space-based infrared sensing is the high-sensitivity detection of small and weak targets. A major innovation in this regard is the design of the infrared detection system indicator, which is influenced by the characteristics of the target background radiation. The effectiveness of space-based infrared detection is significantly challenged by airborne targets, especially civil aircraft. These targets are active in the upper troposphere and lower stratosphere. They exhibit weak and variable radiation characteristics due to complex background clutter and atmospheric attenuation. Aiming to address this issue, this paper proposes a multi-parameter joint optimization method for an airborne target infrared detection system based on the coupling of multiple physical effects. Firstly, the initial optimization of the target detection spectral band in the sky is completed based on the spectral radiation characteristics of the target, the background, and the spectral atmospheric transmittance change characteristics of the target-sky-based detection platform. Subsequently, the detection sensitivity requirements are proposed. Then, a system parameter optimization method is established with the target motion speed limit, earth background limit, and detection sensitivity as the three major boundaries. This method facilitates the creation of an infrared detection index system for air targets.
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Analysis of Infrared Polarization Characteristics and Modeling of Operating Distance on Aerostat Platform in Sea Fog
YE Min-Rui, CUI Wen-Nan, HUANG Xia-Yang, ZHANG Tao
Abstract:
The study aims to reveal the detection advantages of infrared polarization imaging systems on aerostat platforms against the background of sea fog. Firstly, based on the polarization bidirectional reflection distribution function, the study analyzes the variation of polarization characteristics with observation angles, indicating the applicability of infrared polarization in oblique viewing from aerostats. Secondly, using Monte Carlo method and the MRTD model, the study constructs a model for the maximum operating distance of infrared polarization imaging systems, thereby verifying the advantages of infrared polarization imaging over infrared intensity imaging in maintaining features and detection distance under sea fog conditions. This provides theoretical analysis and simulation evidence for the deployment of infrared polarization detection technology on aerostat platforms.
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A near-infrared all-fiber mode monitor based on the mini-two-path Mach-Zehnder interferometer
ZHU Xiao-Jun, LIU Yu, WU Yue, ZHUANG Hao-Ran, SUN Dan, SHI Yue-Chun, CAO Juan, YANG Yong-Jie
Abstract:
A novel near-infrared all-fiber mode monitor based on a mini-two-path Mach-Zehnder interferometer (MTP-MZI) is proposed. The MTP-MZI mode monitor is created by fusing a section of no-core fiber (NCF) and a single-mode fiber (SMF) together with an optical fiber fusion splicer, establishing two distinct centimeter-level optical transmission paths. Since the high-order modes in NCF transmit near-infrared light more sensitively to curvature-induced energy leakage than the fundamental mode in SMF, the near-infrared high-order mode light leaks out of NCF when the curvature changes, causing the MTP-MZI transmission spectrum to change. By analyzing the relationship between the curvature, transmission spectrum, and spatial frequency spectrum, the modes involved in the interference can be analyzed, thereby revealing the mode transmission characteristics of near-infrared light in optical fibers. In the verification experiments, higher-order modes were excited by inserting a novel hollow-core fiber (HCF) into the MTP-MZI. When the curvature of the MTP-MZI changes, the near-infrared light high-order mode introduced into the device leaks out, causing the transmission spectrum to return to its original state before bending and before the HCF was spliced. The experimental verification shows that the MTP-MZI can be used as an all-fiber mode monitoring device to monitor the modes introduced into the optical fiber from the outside, providing experimental and theoretical basis for near-infrared all-fiber mode monitoring in optical information systems.
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Sparsity and Self-Similarity Priors Guided Deep Learning for Blind Image Super-Resolution
GE Sun-Yi, LUO Xiao-Wei, FENG Shi-Yang, WANG Bin
Abstract:
Blind image super-resolution (BISR) aims to restore corresponding high-resolution (HR) images from low-resolution (LR) images with unknown degradation, becoming a research hotspot in the field of computer vision. Due to the ill-posed nature of this problem, the rational selection and utilization of image priors have become key to solving it. However, existing deep learning-based BISR algorithms only employ neural networks to learn the mapping from LR to HR images in an end-to-end manner, only allowing the network to implicitly learn image priors, resulting in somewhat blurry super-resolution results. A deep learning-based BISR algorithm guided by sparsity and self-similarity priors is proposed to address the above issues. Initially, for various LR image inputs, a dynamic linear kernel estimation module is employed to effectively estimate the corresponding blur kernels; Subsequently, a deep unfolding deconvolution filtering module based on the Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) is utilized to explicitly model the sparsity prior of signal, achieving deconvolution restoration of the degraded images; Finally, a dual-path multi-scale large receptive field restoration module leverages the self-similarity prior of images for super-resolution recovery. Experimental results on the public Gaussian8 and DIV2KRK datasets demonstrate that, compared to existing methods, the proposed algorithm not only achieves the highest restoration metrics but also delivers superior visual quality in the recovered images.
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Study on the preparation and spectroscopic ellipsometry of 2H-MoTe2quantum dot films
LI Guo-Bin, HU Kun, ZHANG Tai-Wei, YANG Ao, XIA Yi-Ping, LI Xue-Ming, TANG Li-Bin, YANG Pei-Zhi, WANG Shan-Li, CHEN Sheng-Di, YANG Li, ZHANG Yan
Abstract:
The preparation of quantum dot thin films and the accurate determination of optical constants are particularly important in the development and application of their optoelectronic fields. At present, the optical constants of MoTe2 single-crystal films prepared by mechanical exfoliation and chemical vapor deposition are relatively mature. However, the optical constants of 2H-MoTe2 quantum dot films are rarely reported. 2H-MoTe2 quantum dots were prepared by ultrasonic assisted liquid phase exfoliation, and two sizes of 2H-MoTe2 quantum dots were prepared by changing the type of solvent and ultrasonic order. The optical constants such as refractive index, extinction coefficient and dielectric constant of quantum dot films of two sizes were studied by B-spline model and Tauc-Lorentz model using ellipsometry. The results show that the two sizes of 2H-MoTe2 quantum dots have similar refractive index, extinction coefficient and a wider spectral absorption in the visible to near infrared band. And compared with MoTe2 bulk material, it has a lower dielectric constant.
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Waveform frequency domain matching-based positioning method for Gaofen-7 satellite lidar footprints
ZHOU Si-Han, ZHAO Pu-Fan, YANG Jian, HAN Qi-Jin, WANG Heng, MA Yue, ZHOU Hui, LI Song
Abstract:
The laser altimeter aboard the Gaofen-7 satellite primarily provides elevation control points for imagery. During satellite operations, environmental variations can induce laser pointing offsets, which in turn increase the positioning errors of the footprints, thereby directly reducing the elevation accuracy of the control points. This issue is particularly pronounced in complex mountainous terrains. To enhance the reliability of laser altimeter observations from satellites in such regions, this paper proposed a new laser footprint positioning method based on waveform frequency domain matching. This method utilizes high-precision terrain data for waveform simulation and determines the position of the laser footprint by calculating the correlation between the simulated waveforms and the received waveforms of Gaofen-7 in the frequency domain. Additionally, systematic deviations in laser pointing are derived from the joint computational results of multi-footprint frequency domain matching. Experiments were conducted using in three regions: central Montana, western Wyoming, and eastern Utah in the United States. The results indicate that the standard deviations of footprint planar offset distances, planar true north pinch angles, and equivalent laser pointing deviation angles obtained with this method are all superior to those achieved with the time-domain waveform matching method. The findings underscore the advantages of frequency-domain waveform matching in achieving high-precision footprint localization, thereby providing a robust foundation for enhancing the utility of satellite laser altimeter observations in challenging environments and facilitating the correction of laser altimeter pointing errors.
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Simulation and Evaluation of Mid-Infrared Sea Surface Sun Glint Directional Radiation
zhangzhenwu, WANG Ning, MA Ling-Ling, ZHANG Bei-Bei, ZHAO Yong-Guang, LI Wan
Abstract:
The energy received in the mid-infrared (MIR) band at the sensor's aperture includes both reflected solar energy and the emitted energy from the Earth's surface. Typically, the reflected solar energy in this band is weak; however, under certain conditions, such as in sun glint regions over the sea surface, the reflected solar energy detected by the MIR channel can be substantial. Currently, the application of sun glint physical models in the MIR band is not well understood. This study investigates the accuracy of applying different visible light and shortwave infrared sun glint models to the MIR band. The paper selects three models: Breon-Henriot, Ebuchi-Kizu, and Wu, and evaluates the sensitivity of each sun glint model. Subsequently, using four selected MODIS sun glint images as data sources, and combining them with ERA5 reanalysis data matched to satellite data for atmospheric parameter calculations, the solar radiation intensity reflected by the sea surface is computed using the three models. The accuracy of each model is then further validated with an MIR radiative transfer model. The results show that the Breon-Henriot model generally performs best in terms of correlation coefficient and root mean square error compared to MODIS measurements. These findings not only extend the application range of sun glint models in the MIR band but also enhance the MIR forward modeling system, providing new theoretical support for MIR radiative transfer and improving the effectiveness and accuracy of MIR remote sensing products in climate change monitoring and sea surface temperature dynamic analysis.
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A High Output Power 340GHz Balanced Frequency Doubler Design Based on Linear Optimization Method
Zhicheng Liu, Jingtao Zhou, Jin Meng, Haomiao Wei, Chengyue Yang, Yongbo Su, Zhi Jin, Rui Jia
Abstract:
In this paper, a linear optimization method(LOM) for the design of terahertz circuits is presented, aimed at enhancing simulation efficacy and reducing the time of the circuit design workflow. This method enables the rapid determination of optimal embedding impedance for diodes across a specific bandwidth to achieve maximum efficiency through harmonic balance simulations. By optimizing the linear matching circuit with the optimal embedding impedance, the method effectively segregates the simulation of the linear segments from the nonlinear segments in the frequency multiplier circuit, substantially increasing the speed of simulations. The design of on-chip linear matching circuits adopts a modular circuit design strategy, incorporating fixed load resistors to simplify the matching challenge. Utilizing this approach, a 340GHz frequency doubler was developed and measured. The results demonstrate that, across a bandwidth of 330GHz to 342GHz, the efficiency of the doubler remains above 10%, with an input power ranging from 98mW to 141mW and an output power exceeding 13mW. Notably, at an input power of 141mW, a peak output power of 21.8mW was achieved at 334GHz, corresponding to an efficiency of 15.8%.
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BDMFuse: Multi-Scale Network Fusion for Infrared and Visible Images Based on base and Detail Features
Si Hai-ping, Zhao Wen-rui, Li Ting-ting, Li Fei-tao, Feiernanduo.Basang, Sun Chang-xia, Li Yan-ling
Abstract:
The result of infrared and visible image fusion should highlight the significant targets of the infrared image while preserving the visible light texture details. In order to satisfy the above requirements, this paper proposes an automated encoder-based infrared and visible image fusion method. The encoder constructs both a base encoder and a detail encoder according to the optimization objective. The base encoder extracts low-frequency information from the image, while the detail encoder captures high-frequency information. Since this extraction method may miss some information, we introduce a compensation encoder to supplement the missing information. Additionally, we introduce multi-scale decomposition for the encoder to extract image features more comprehensively. The image features obtained by the encoders are then fed into the decoder. The decoder first adds the low-frequency, high-frequency and compensatory information to obtain multi-scale features. An attention map is derived from these multi-scale features and multiplied with the fused image at the corresponding scale. The Fusion module is introduced in the multi-scale fusion process to achieve image reconstruction. The network proposed in this paper demonstrates its effectiveness on the TNO, RoadScene, and LLVIP datasets. Experiments show that our network can better perceive changes in light, effectively extract image detail information, and produce fused images that are more aligned with human visual perception.
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Urban Tree Species Classification with Multispectral Airborne LiDAR
Peilun Hu, Yuwei Chen, Mohammad Imangholiloo, Markus Holopainen, Yicheng Wang, Juha Hyyppä
Abstract:
Urban tree species provide various essential ecosystem services in cities, such as mediating urban temperature, isolating noise, fixing carbon, and alleviating the urban heat island effect. The quality of these services is influenced by species diversity, tree growth status, and the distribution and composition of trees. Traditionally, data about urban trees has been gathered through field data collection and manual interpretation of remote sensing images. In this study, we evaluate the capacity of using Multispectral Airborne Laser Scanning (ALS) data to classify 24 common urban roadside tree species in Espoo, Finland. We utilized tree crown structure information, intensity features, and spectral information for classification. The results demonstrated an overall accuracy of 71.5% using multispectral LiDAR data, highlighting that combining structural and spectral information in a single frame could enhance classification accuracy. In the future, we will focus on identifying the most important features in species classification and finding algorithms with higher efficiency and accuracy.
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Tidal flats extraction in the coastal zone based on time-series Sentinel-2 imagery and near-infrared tidal flats indices
zhourujia, XIA Qing, ZHENG Qiong, ZHU Li-Hong, LI Bin, Li Jianhua, SONG Jia
Abstract:
When extracting coastal zone tidal flats using remote sensing transient images, the influence of tides greatly limits the accuracy of tidal flat spatial distribution extraction. In this paper, based on the Google Earth Engine (GEE) cloud platform, a coastal zone tidal flats extraction method by combining the time-series Sentinel-2 image and the tidal flats index is proposed. First, based on the Sentinel-2 time-series image data, we use the quantile synthesis method to generate high- and low-tide images, and then analyze the spectral reflectance characteristics of different land classes on the high- and low-tide images. A NIR-band tidal flat extraction index that excludes the interference of the tidal transient is constructed. Secondly, the image spectral information and the tidal flat extraction index are input into a machine learning algorithm to realize fast and efficient extraction of the tidal flat. Finally, the separability of the tidal flats index and the universality are investigated. The results show that the tidal flats extraction index constructed in this research had a good separability for tidal flats, the overall accuracy of tidal flats extraction was 93.02%, the Kappa coefficient was 0.86, and the proposed method has good applicability to remote sensing images containing near-infrared bands. This method can realize automatic and rapid tidal flat extraction, and provide data support for the sustainable management and protection of coastal zone resources.
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Detection and quantification of water / ice in typical lunar minerals using Raman spectroscopy
WEN Dao-Yuan-Tian, Zhao Hai-Ting, LIU Xiang-Feng, XU Wei-Ming, XU Xue-Sen, LEI Xin-Rui, SHU Rong
Abstract:
The water in lunar materials can promote the evolution of lunar geology and environment and provide the necessary conditions for the utilization of lunar resource. Owing to the low resolution of lunar remote sensing methods, it is difficult to obtain direct evidence of water / ice or determine its form of occurrence. Laser Raman spectroscopy can obtain fingerprint information of minerals and water bodies without the need for illumination, sample pretreatment, and non-destructive, providing direct and favorable information regarding the type, distribution range, and content of lunar materials. In this study, Raman spectroscopy was used to detect the water-containing characteristics of typical lunar rocks/minerals and forms such as adsorbed water, ice, crystalline water, and hydroxyl-structured water, and quantitatively analyze the water content. First, a 532 nm laser micro-Raman spectroscopy was used to identify and analyze the water-containing signals of typical lunar minerals and various forms of water in lunar soil simulants. Second, the detection limits of adsorbed water, crystalline water, and hydroxyl-structured water in lunar soil simulants were examined and analyzed, along with the patterns between their content and signal intensity. Finaly, linear regression (LR), ridge regression (RR), and partial least squares regression (PLSR) were employed for quantitatively analyze of the contents of three forms of water in the lunar soil simulants. The results show that (1) the characteristic spectral peaks of the four forms of water in the lunar soil simulants can be clearly identified. The peak distribution regions of the lunar soil simulants components and water bodies are located at 100-1700 cm-1 and 2600-3900 cm-1, respectively. The characteristic spectral peaks of water are manifested as a combination of broad envelope peaks of hydrogen-bonded OH and sharp peaks of non-hydrogen-bonded OH stretching vibrations in varying proportions. (2) Detection limits of adsorbed water, crystalline water (MgSO4·7H2O), and hydroxyl water (Al2Si2O5(OH)4) in the lunar soil simulants are 1.3 wt%, 0.8 wt%, and 0.3 wt%, respectively. (3) A linear relationship exists between the intensity of water-containing peaks and the water content in the lunar soil simulants, with root mean square errors of 1.75 wt%, 1.16 wt%, and 1.19 wt% obtained through LR, RR, and PLSR.
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Simulation design of short-wave infrared heterogeneous phototransistor for weak light detection
LIAO Ke-Cai, HUANG Min, WANG Nan, LIANG Zhao-Ming, ZHOU Yi, CHEN Jian-Xin
Abstract:
The sensitivity of the detector is the core technical indicator of the infrared detector. Short-wave infrared detector has low dark current and the sensitivity will be limited by the inherent read-out circuit noise of the detection system. Therefore, it is an effective way to further enhance the sensitivity by introducing internal gain into the detector. Heterogeneous phototransistor takes advantages of high gain, low operating bias, and low excess noise, which provides novel approach for high-sensitive detection. This paper mainly focuses on the simulation design of InGaAs/GaAsSb type-II superlattice short-wave infrared phototransistor, and studies the dependence of the device size on the optoelectronic characteristics. The results show that a higher gain, a lower dark current, and a faster response can be achieved by a smaller base size. Based on the optimization design of size structure, a sensitivity with a noise equivalent photon lower than 10 can be achieved, which provides a new technical approach to achieve high-sensitive heterogeneous phototransistor detector.
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Infrared small target detection method based on nonconvex tensor Tuck decomposition with factor prior
yangjungang, 刘婷, liuyongxian, liboyang, wangyingqian, shengweidong, anwei
Abstract:
Low-rank and sparse decomposition method (LRSD) has been widely concerned in the field of infrared small target detection because of its good detection performance. However, existing LRSD-based methods still face the problems of low detection performance and slow detection speed in complex scenes. Although existing low-rank Tuck decomposition methods achieve satisfactory detection performance in complex scenes, they need to define ranks in advance according to experience, and too large or too small the estimated ranks will lead to missed detection or false alarms. Meanwhile, the size of rank is different in different scenes. This means that they are not suitable for real-world scenes. To solve this problem, this paper uses non-convex rank approach norm to constrain latent factors of low-rank Tucker decomposition, which avoids setting ranks in advance according to experience and improves the robustness of the algorithm in different scenes. Meanwhile, an symmetric GaussSeidel (sGS) based alternating direction method of multipliers algorithm (sGSADMM) is designed to solve the proposed method. Different from ADMM, the sGSADMM algorithm can use more structural information to obtain higher accuracy. Extensive experiment results show that the proposed method is superior to other advanced algorithms in detection performance and background suppression.
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2002,21(3):161-166, DOI:
Abstract:
A segmentation model that combines the Mumford Shah(M S) model and narrow band scheme of level set was presented. The disadvantage of Mumford Shah model is computationally time consuming. In each step of its iteration, the data of whole image have to be renewed, which is unbearable for segmentation of large image or 3D image. Therefore, a fast segmentation model was introduce, which combines the M S model and narrow band scheme by a new initialization method. The new initialization method is based on fast marching method, and the computing time decreases to O(N) . In each step of iteration, the new segmentation model only deals with the data in a narrow band instead of the whole image. The experiments show that the two models can obtain almost the same segmentation result, but the computing time of new narrow band M S model is much less than that of M S model.
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2001,20(3):184-188, DOI:
Abstract:
测量了几种不同处理的Cd1-xZnxTe(x=0.04)表面的傅里叶变换拉曼散射光谱和电流－电压（I－V）特性。通过分析拉曼光谱反Stokes分量，并与表面I－V特性进行比较，结果表明与表面处理相联系的晶格声子的行为反映了表面完整性的变化，Te沉淀是影响表面质量的关键因素，并对有关表面处理方法的实际应用进行了讨论。
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GUO Li Xin 1) KIM Che Young 2)
2003,22(2):132-136, DOI:
Abstract:
根据粗糙面基尔霍夫小斜率近似研究了脉冲波入射时实际海谱分布的一维分形海面的电磁散射。分析了毫米波入射时不同分维、入射角和入射中心频率下双频散射截面的散射角分布。结果表明分形海面的双频散射截面在镜反射方向有最大的相关带宽，随着海面分维的减小、入射中心频率和入射角的增加，该相关带宽是增大的。对于入射功率为δ函数时的散射波功率是一个具有一定脉冲展宽的散射脉冲，且脉冲展宽与相关带宽成反比关系。
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FuY ChiragwandiZ GoethbergP WillanderM
2003,22(6):401-405, DOI:
Abstract:
We have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in the optical spectrum are determined by the density of electronic states of the system, and the symmetries and intensities of these peaks can be improved by reducing the dimensionality of the system. Optical gain requires in general a population inversion, whereas for a quantum-dot system, there exists a threshold value of the population inversion.
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HU Zhi Gao WANG Gen Shui HUANG Zhi Ming CHU Jun Hao
2002,21(3):175-179, DOI:
Abstract:
采用溶胶－凝胶法在石英玻璃衬底上制备出均匀透明的无定形PbTiO3薄膜，并对其 光学性质进行了详细的研究，发现其折射率的波形符合经典的Cauchy函数。由半导体理论计算得到无定形的PbTiO3薄膜的光学禁带宽度为3．84eV.FTIR透射光 谱研究表明无定形PbTiO3薄膜在中红外波段没有吸收峰出现，对于在550℃下 快速热退火得到的PbTiO3薄膜，通过远红外反射光谱测量，观察到了6个约外活性声子膜。
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XU Yun, WANG Yi-Ming, WU Jing-Zhu, ZHANG Xiao-Chao
2010,29(1):53-56, DOI:
Abstract:
NIRS was used in rapid qualitative and quantitative detection for melamine of pure milk in this paper. Experiment was conducted by preparing two groups pure milk samples which melamine content is different for qualitative analysis and quantitative analysis. By combining NIRS technology with the cluster analysis method, A effective classification can be made on the two kinds of milk samples with and without melamine; To achieve this, spectrum pretreatment and wave length choice methods were employed before model optimization. The results showed that NIR models of predicting melamine content in pure milk has good stability and predictive ability.This paper suggested that NIR could be used as a quick, green and convenient method for predicting melamine content of dairy.
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CHENG Jian, ZHOU Yue, CAI Nian, YANG Jie
2006,25(2):113-117, DOI:
Abstract:
The particle filter is an effective technique for the state estimation in non-linear and non-Gaussian dynamic systems. A novel method for infrared object robust tracking based on particle filters was proposed. Under the theory framework of particle filters, the posterior distribution of the infrared object is approximated by a set of weighted samples, while infrared object tracking is implemented by the Bayesian propagation of the sample set. The state transition model is chosen as the simple second-order auto-regressive model, and the system noise variance is adaptively determined in infrared object tracking. Infrared objects are represented by the intensity distribution, which is defined by the kernel-based density estimation. By calculating the Bhattacharyya distance between the object reference distribution and the object sample distribution, the observation probability model is constructed. Experimental results show that our method is effective and steady.
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WU Yan 1), 2) ZHANG Li Ming 2)
2002,21(3):189-194, DOI:
Abstract:
Based on bias variance model, a novel method of dynamically tuning the regularization coefficient by fuzzy rules inference was proposed. The fuzzy inference rules and membership functions were effectively determined. Furthermore, the method was compared with the traditional BP algorithm and fixed regularization coefficien's method. The result is that the proposed method has the merits of the highest precision, rapid convergence and best generalization capacity. The capacity proposed method is shown to be a very effective method by several examples simulation.
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2008,27(2):123-128, DOI:
Abstract:
多数传统分类算法应用于高光谱分类都存在运算速度慢、精度比较低和难以收敛等问题.本文从支持向量机基本理论出发建立了一个基于支持向量机的高光谱分类器,并用国产OMIS传感器获得的北京中关村地区高光谱遥感数据进行试验,分析比较了各种SVM核函数进行高光谱分类的精度,以及网格搜寻的方法来确定C和愕闹?结果表明SVM进行高光谱分类时候径向基核函数的分类精度最高,是分类的首选.并且与神经网络径向基分类算法以及常用的最小距离分类算法进行比较,分类的精度远远高于SVM分类算法进行分类的结果.SVM方法在高光谱遥感分类领域能得到广泛的应用.
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2010,29(1):63-68, DOI:
Abstract:
A novel infrared target extraction algorithm based on particle swarm optimization particle filter(PSOPF) was proposed. The problem of infrared target extraction was analyzed and solved in the view of state estimation. In the framework of particle filter, the threshold state space on the gray-variance weighted information entropy and the grey value of each pixel was based on extraction results evaluation function, which integrated grey, entropy, gradient and spatial distribution of pixels. Finally, the weighted average of all the particles was used as target extraction threshold. The experiment results prove that the proposed algorithm is effective and robust.
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2010,29(1):69-74, DOI:
Abstract:
Image segmentation is one of the difficult problems in computer vision research. Recently spectral clustering has a wide application in pattern recognition and image segmentation. Compared with traditional clustering methods, it can cluster samples in any form feature space and has a global optimal solution. Originating from the equivalence between the spectral clustering and weighted kernel K-means, the authors proposed a spectral clustering algorithm with spatial constraints based on the spatially coherent property of images, also named continuous property. The spatially coherent property means that pixels in the neighbor region should share the same label assignment with the centre one with a high probability. The algorithm adds a term of spatial constraints to the objective function of weighted kernel K-means and makes the minimization of the objective function be equivalent to the spectral clustering through approximation. Experimental results show that our proposed algorithm outperforms the traditional spectral clustering in image segmentation.
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2001,20(3):207-210, DOI:
Abstract:
A novel pixel level image fusion scheme was presented based on multiscale decompositon. First, the wavelet transform is used to perform a multiscale decomposition of each image. Then, the wavelet coefficients of fused image are constructed using multiple operators according to different fusion rules. This approach is successfully used to fuse the infrared and visible light images. The experimental results show that the fusion scheme is effective and the fused images are more suitable for human visual or machine perception.
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HE Yang, YANG Jin, MA Yong, LIU Jian-Bo, CHEN Fu, LI Xin-Peng, YANG Yi-Fei
2016,35(5):600-609, DOI: 10.11972/j.issn.1001-9014.2016.05.015
Abstract:
Traditional fire detection methods use the high temperature emission characteristics in mid or thermal infrared bands of the MODIS or AVHRR data to extract burning area. It is very hard for these methods to identify small fire regions such as sub-pixel due to the limitation of spatial resolution. Recently researchers have found that shortwave infrared (SWIR) data can also be used to identify and detect high temperature targets. Compared with the thermal infrared data, SWIR has a big discrimination against different features with different temperature. Thus it can identify accurately the location of high temperature targets. In this paper, we acquired fire point products by using Landsat-8 OLI data which has spatial resolution up to 30 m. The main procedure includes two steps. The improved Normalized Burning Ratio Short-wave(NBRS) is calculated at first to adaptively acquire suspected fire points based on the spectral characteristics of fire points in the near infrared and shortwave infrared. Then most false positive points are excluded based on the relationship between peak value in shortwave infrared band of fire points. This algorithm is capable of detecting the burning area around 10% in one pixel. With the premise of avoiding the interference of cloud and constructions, it can also keep a nearly 90% accuracy and low missing rate around 10%.
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ZHANG Qian, TANG Li-Bin, LI Ru-Jie, XIANG Jin-Zhong, HUANG Qiang, LIU Shu-Ping
2019,38(1):79-90, DOI: 10.11972/j.issn.1001-9014.2019.01.014
Abstract:
With the rapid development of graphene industry, graphene oxide has attracted much attention as an important intermediate product for the preparation of graphene. Due to its excellent physical and chemical properties, it has been widely used in multitudinous fields. Various structural models, preparation methods, properties and related applications, as well as the reduction of graphene oxide are summarized. The choice of oxidants and reduction agents were found to be important in the reaction. The basic selective principles are discussed after comparing various methods. Finally, it is pointed out that there are still some problems to be solved in the preparation and reduction of graphene oxide. The prospect of graphene oxide on its development and influence will also be evaluated.
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EFFECTS OF APODIZATION FUNCTIONS OF IMAGING FOURIER TRANSFORM SPECTROMETER ON RECONSTRUCTED SPECTRUM
ZHANG Wen-Juan, ZHANG Bing, ZHANG Xi, GAO Lian-Ru, ZHANG Wei
2008,27(3):227-233, DOI:
Abstract:
随着搭载干涉成像光谱仪HJY20-1-A的我国环境与减灾遥感卫星HJ-1A即将发射,我国干涉光谱成像研究也从实验室开始走向实用化.在干涉光谱成像过程中,切趾函数处理是干涉成像光谱仪光谱复原过程中的一个重要环节,对复原光谱的精度有着极其重要的影响.根据HJY20-1-A的参数设置,文中首先模拟了24种典型地物对应于HJY20-1-A和其它最大光程差设置的干涉成像光谱仪数据,在不同切趾函数作用下的复原光谱,结果表明Hanning函数是其中最有效、最为稳定的切趾函数,同时发现切趾函数的应用虽然可以提高复原光谱的精度,但与真实光谱仍存在一定差距,尤其对应HJY20-1-A,复原光谱的精度更加有限.在以上分析基础上,提出了基于仪器线型函数标准化的光谱复原改进算法,实验结果证实了该方法可以显著提高复原光谱精度,尤其适用于最大光程差较小的空间调制型干涉成像光谱仪.最后,就HJY20-1-A复原光谱对3种典型植被指数求解,进一步证明了该方法的有效性.
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SUN Jun-Ding, DING Zhen-Guo, ZHOU Li-Hua
2005,24(2):135-139, DOI:
Abstract:
A new image retrieval algorithm based on image entropy and spatial distribution entropy was presented. At first a more robust method, which can remove the influence of the symmetry of entropy, was proposed to extract the global color feature. Then color spatial distribution entropy vector for each color channel was also introduced to represent the spatial color information. After that, the moments were adopted to reduce the dimension of color spatial distribution entropy. In the end, a low dimensional vector which includes the global and spatial information was used as index for color image retrieval. The experiment results show that the new method gives better performance than color histogram.
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JIANG Wei Dong CHEN Zen Ping ZHUANG Zhao Wen GUO Gui Rong
2001,20(2):111-116, DOI:
Abstract:
The simulation methods of radar clutter with given amplitude distribution and power spectrum were described, and the simulation results of radar clutter were given. A scattering center model of frequency domain of radar target was presented under the clutter environment and its solution method was studied. Finally, the experimental results of simulation data and the measurement data of aircraft scale model were given.
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WU Xiang, PEI Zhi-Bin, QU Shao-Bo, XU Zhuo, ZHANG Jie-Qiu, MA Hua, WANG Jia-Fu, WANG Xin-Hua, ZHOU Hang
2011,30(5):469-474, DOI:
Abstract:
By adjusting the effective permittivity of the unit cell, a new method of constructing metamaterial band-pass frequency selective surface was proposed. The effective permittivity of continuous conducting wires is negative below the plasma frequency and thus a stop-band occurs. By combining the continuous conducting wires with cut wires, we realized a one-dimensional frequency selective surface. Both the theory analysis and simulation results demonstrated the facility and feasibility of the method. We also designed a wide-angle and polarization-independent frequency selective surface based on this method. Two samples were fabricated to validate the proposed method; the experiment results were fairly consistent with the simulation results. The proposed method eliminates the complicated calculation and excessive parameter optimization process. It paves a new way of designing frequency selective surfaces and is of important reference values for fabricating THz frequency selective surface as well as multi-band, tunable and miniaturized frequency selective surfaces.
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ZHANG Yu-Hong, CHEN Zhan-Guo, JIA Gang, SHI Bao, REN Ce, LIU Xiu-Huan, WU Wen-Qing
2008,27(3):165-169, DOI:
Abstract:
首次测量了硅材料在1.3μm波长处,基于克尔效应和弗朗兹-凯尔迪什效应的电致双折射,进而计算出三阶非线性极化率张量X(3)的分量X(3)xyxy.观测到弗朗兹-凯尔迪什效应引起的折射率变化与入射光的偏振态有关.在实验中,测得了由克尔效应引起的折射率之差为⊿n=5.49×10-16E20,而弗朗兹-凯尔迪什效应引起的折射率之差为⊿n'=2.42×10-16E2.50.
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SHI Jun-Sheng 1, 2, JIN Wei-Qi 1, WANG Ling-Xue 1
2005,24(3):236-240, DOI:
Abstract:
With the development and the application of visible-IR image fusion techniques in color vision night, evaluating the performance of image-fused algorithms is becoming an important aspect. In this study, three basic visual evaluation factors, target detection, details and colorfulness, were presented for evaluating perceptual quality of color fused images, and the degree of correlation between the perceptual quality and the three evaluation factors was investigated. Visual evaluation experiment on the color images fused visible and IR images of ten scenes by four fusion algorithms was conducted. The experimental results show that the fuesd images have good performances in target detection, the correlation coefficient between the perceptual qulity and details is 0.89, and the correlation coefficient between the perceptual qulity and colorfulness is 0.75 . It indicates that details are the main factor and the colorfulness plays an important role when targets are beyong the detected level.
