Volume 41,2022 Issue 5

Infrared Materials and Devices

• Study on As diffusion control of MBE-grown P-on-N HgCdTe

  SHEN Chuan, YANG Liao, LIU Yang-Rong, BU Shun-Dong, WANG Gao, CHEN Lu, HE Li

  2022,41(5):799-803, DOI: 10.11972/j.issn.1001-9014.2022.05.001

  Abstract: (37) HTML (15) PDF (877.74 KKB)(89)

  Abstract:

  As diffusion control caused by the thermal annealing of in-situ As-doped HgCdTe grown by molecular beam epitaxy （MBE） was studied. HgCdTe with controllable As diffusion length is obtained at a lower annealing temperature， which is easy to form a PN junction profile that meets the design parameters. It provides a basis for the subsequent development of new HgCdTe FPA devices. It is found that the longitudinal distribution of As concentration of the in-situ As-doped HgCdTe changed under different Hg pressures during the thermal annealing process. And through theoretical calculations， As diffusion coefficients under different Hg pressures are obtained. Meanwhile， the dark current simulation of HgCdTe P-on-N structure with different As diffusion lengths was carried out through numerical simulation， which verified the importance of deep-advancing process for As-doped HgCdTe PN junction.

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• Planar wavelength-extended In_0.75Ga_0.25As detector with 2.2-μm cut-off wavelength

  CHENG Ji-Feng, LI Xue, SHAO Xiu-Mei, LI Tao, WANG Hong-Zhen, MA Ying-Jie, YANG Bo, GONG Hai-Mei

  2022,41(5):804-809, DOI: 10.11972/j.issn.1001-9014.2022.05.002

  Abstract: (27) HTML (11) PDF (1.08 MKB)(65)

  Abstract:

  Planar-type 2.2 μm wavelength-extended InGaAs photodetectors （PDs） using the sealed-ampoule diffusion method was reported. The zinc arsenide powder was used as the dopant source， which was driven into the cap of the In_0.75Al_0.25As/In_0.75Ga_0.25As/In_0.75Al_0.25As hetero structure materials grown by molecular beam epitaxy （MBE）， using a SiN_x as diffusion mask deposited by ICP-CVD. The junction depth， the lateral collection width of photogenerated carriers， the I-V characteristics， the spectral response and the detectivity of the detector at different temperatures were analyzed. The results indicate that the PD exhibits a low dark current density of 0.69×10^-9 A/cm² at -10 mV at 150 K. The cutoff wavelength and peak wavelength were 2.12 μm and 1.97 μm. The peak detectivity， peak responsivity and quantum efficiency was 1.01×10¹² cm·Hz^1/2/W， 1.29 A/W and 82% respectively. These results suggest that the planar-type InGaAs can reach high performance.

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• Research on dark current characteristics of InAsSb Barrier-blocking infrared detector

  CHEN Dong-Qiong, WANG Hai-Peng, QIN Qiang, DENG Gong-Rong, SHANG Fa-Lan, TAN Ying, KONG Jin-Cheng, HU Zan-Dong, TAI Yun-Jian, YUAN Jun, ZHAO Peng, ZHAO Jun, YANG Wen-Yun

  2022,41(5):810-817, DOI: 10.11972/j.issn.1001-9014.2022.05.003

  Abstract: (24) HTML (8) PDF (1.87 MKB)(77)

  Abstract:

  The carrier lifetimes determined by radiative and Auger 1 recombination in InAs_1-xSb_x were calculated at different temperatures. For n-type InAsSb material， at low temperatures， the carrier lifetime is limited by the radiative recombination， while at high temperatures， the Auger 1 process is dominant. An analytical model of dark current for barrier blocking detectors was discussed， by adding a heavily doped n-type InAsSb electrode on the other side of the absorber layer to form an nBnn⁺ structure to deplete the carriers in absorber， the hole concentration in absorption region was decreased about two orders of magnitude， further reducing the dark current of the devices. InAsSb-based nBnn⁺ barrier devices have been successfully fabricated and characterized. At 150 K， the devices displayed a dark current density as low as 3×10^-6 A/cm²， the dark current density of the detectors was fitted by the nBn-based architecture analytical current model， the experimental results indicated that due to the p-type doping of the barrier layer， a depletion region was formed in the InAsSb absorber region， resulting in incomplete inhibition of G-R current. At temperatures below 180 K， the dark current of the detector is limited by G-R process， at temperatures above 180 K， the dark current of the device is limited by diffusion current.

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• Very long wave HgCdTe infrared focal plane detector

  LI Xiong-Jun, ZOU Lei, ZHAO Peng, YANG Chao-Wei, XIONG Bo-Jun, WANG Xiang-Qian, ZHANG Ying-Xu, LIU Yan-Zhen, LI Hong-Fu, ZHAO Yu-Song, ZHANG Shao-Yu, LI Li-Hua

  2022,41(5):818-824, DOI: 10.11972/j.issn.1001-9014.2022.05.004

  Abstract: (22) HTML (6) PDF (1.57 MKB)(87)

  Abstract:

  Very long wave 640×512 FPAs with 25 μm pixel pitch and cutoff wavelength of 13.23 μm， 14.79 μm respectively at 77 K were prepared by the arsenic ion implanted p-on-n planar junction technology. The basic performance and dark current of the FPAs are characterized and analyzed. The results show that the quantum efficiency of the VLWIR 640×512 FPAs with λ_c （77 K） =13.23 μm is 55%， the average NETD is 21.5 mk， with an operability of 99.81%； The quantum efficiency of the VLWIR 640×512 FPAs with λ_c （77 K） =14.79 μm is 45%， the average NETD is 34.6 mK， with an operability of 99.28%. The R₀A figures of merit at liquid nitrogen temperature are 19.8 Ω·cm² and 1.56 Ω·cm² respectively， which reaches the predicted value of the "rule07" heuristic law， and the device noise is mainly limited by current shot noise. The results show that the performances of FPAs are at the state of the art.

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Terahertz and Millimeter Wave Technology

• Study of dual-comb terahertz quantum cascade lasers based on polarization modulation

  YANG Si-Jia, LI Zi-Ping, LIAO Xiao-Yu, WANG Chen-Jie, LI Hua, CAO Jun-Cheng

  2022,41(5):825-830, DOI: 10.11972/j.issn.1001-9014.2022.05.005

  Abstract: (21) HTML (9) PDF (1.01 MKB)(61)

  Abstract:

  Dual-comb realized by terahertz quantum cascade lasers （THz QCL） has important applications in spectral detection， distance measurement and imaging. The dual-comb signal is heavily dependent on the THz coupling optical power. The THz QCL light is linearly polarized， and a linear polarizer is inserted into the optical path of the dual-comb. The polarizer is rotated to achieve the effect of adjusting the THz light intensity. The dependence of the THz QCL dual-comb spectrum and power on the polarization angle is systematically investigated and it lays the foundation for the realization of a highly stable THz dual-comb light source and application.

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• Retrieval of supercooled water in convective clouds over Nagqu of the Tibetan Plateau using millimeter-wave radar measurements

  REN Tao, ZHENG Jia-Feng, LIU Li-Ping, ZOU Ming-Long, CHEN Shao-Jie, HE Jing-Shu, LI Jian-Jie

  2022,41(5):831-843, DOI: 10.11972/j.issn.1001-9014.2022.05.006

  Abstract: (14) HTML (6) PDF (2.05 MKB)(53)

  Abstract:

  The identification of supercooled water in convective clouds has always been a difficult point in meteorological sounding. Based on Doppler spectra of a Ka-band millimeter-wave radar and relevant radiosonde data， an algorithm for identifying and retrieving supercooled water in convective clouds of the Tibetan Plateau was proposed. Subsequently， retrieval effects of the algorithm were analyzed using two convective cases， and verified by comparing with measurements of a co-located microwave radiometer （MWR）. Finally， the difference in results of the algorithm and other three previous methods was also discussed. The main findings are as follows： the stratocumulus， cumulus congestus， and altocumulus clouds over Nagqu are dominated by updrafts with rapid changes on the hydrometeor phase in the vertical orientation， resulting in widely distributions of the formed supercooled particles in terms of their reflectivity， effective radius and liquid water content. Supercooled particles of different convective cloud types also locate at different cloud body positions. The velocity of the in-cloud updraft is highly and positively correlated with the reflectivity， effective radius and liquid water content of supercooled water. They possess similar temporal variations and coincident spatial distributions. The radar-derived liquid water path is also proved to agree well with the counterparts of MWR with similar temporal variations and value peaks. Their correlation coefficients can approach 0.63~0.79. Compare with three previous methods， results from the proposed algorithm can be more reasonable on the retrieved supercooled water positions and parameters.

• Distortions of terahertz pulses induced by the air coherent detection technique

  DU Hai-Wei, LONG Jiang

  2022,41(5):844-849, DOI: 10.11972/j.issn.1001-9014.2022.05.007

  Abstract: (10) HTML (4) PDF (711.17 KKB)(44)

  Abstract:

  Terahertz air coherent detection technique is a broadband detection method， which has been widely used in the broadband terahertz technology after its demonstration in the experiment. The frequency response of this method is determined by the duration of the probe laser pulse. Thus， the different probe lasers might induce distortions of terahertz pulses during the detection process. In this paper， the distortions and the energy loss of the terahertz pulses induced by the air coherent detection technique are quantitatively investigated based on the simulations. The results show that the pulse distortions and the energy loss depend on the duration of the probe laser pulse and the central frequency of terahertz pulse to be detected. This work will help to estimate the influence of the air coherent detection technique in the broadband terahertz technology.

• Relationship between radar reflectivity factor and ice water content of non-spherical cirrus ice crystals at 220 GHz

  WANG Biao, HUO Yi-Wei, GUO Xing, WU Jia-Ji

  2022,41(5):850-855, DOI: 10.11972/j.issn.1001-9014.2022.05.008

  Abstract: (15) HTML (7) PDF (1.39 MKB)(42)

  Abstract:

  For the practical needs in the data processing of terahertz radar，the discrete dipole approximation method is used to calculate the backscattering cross-section of non-spherical ice crystals with different shapes. Based on the latest refined ice cloud model， the relationship between the radar reflectivity factor Z_m and ice water content I in 220 GHz is established. The calculation results show that both the shapes of the non-spherical ice crystals and the ice cloud model have a particular influence on the Z_m-I relationship. This study has application value for cloud parameter inversion of mid-latitude cirrus clouds， and it can be helpful for the development of terahertz radar in the detection of clouds.

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• Millimeter wave Schottky diode characterization and on-wafer measurement

  ZHANG Ao, GAO Jian-Jun

  2022,41(5):856-862, DOI: 10.11972/j.issn.1001-9014.2022.05.009

  Abstract: (6) HTML (7) PDF (1.13 MKB)(48)

  Abstract:

  In this paper， the one-port and two-port measurement methods for millimeter wave Schottky diodes are developed， and the corresponding test structures are designed. The variation of cut-off frequency with parasitic resistance and zero bias intrinsic capacitance are analyzed. The equivalent circuit models of small signal and large signal are given. A commercial Schottky diode has been used to extract the small signal model parameters. The experimental results show that the S-parameters agree well under on and off bias condition.

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• High power 510 GHz monolithic integrated frequency tripler for local oscillation sources in heterodyne receiver

  HE Yue, TIAN Yao-Ling, ZHOU Ren, JIANG Jun, LIN Chang-Xing, SU Wei

  2022,41(5):863-870, DOI: 10.11972/j.issn.1001-9014.2022.05.010

  Abstract: (9) HTML (3) PDF (1.69 MKB)(54)

  Abstract:

  A high power 490~530 GHz monolithic integrated frequency tripler is demonstrated based on Gallium Arsenide material. Based on the proposed symmetrical and balanced configuration， the tripler could not only achieve good amplitude and phase balances for efficient power synthesis， but also provide a DC bias path without any bypass capacitor to ensure efficient frequency doubling efficiency. Tolerance simulations are also carried out to analyze the effects of key electrical and structural parameters of the diode on the frequency doubling performance in order to maximize the frequency doubling performance. Finally， the developed 510 GHz triplet， driven by approximately 80-200 mW input power， has an output power of 4-16 mW in the frequency range of 490~530 GHz， where the peak frequency doubling efficiency is 11%. At the 522 GHz frequency point， the triplex produces a maximum output power of 16 mW driven by an input power of 218 mW. The triplexer will later be used as the local oscillator source of a 1 THz solid-state external super outlier mixer.

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• Design of a 1 030 GHz mixer and a 750~1 100 GHz tripler based on thin-film technology

  MENG Jin, ZHANG De-Hai, NIU Bin, ZHU Hao-Tian, LIU Si-Yu, FAN Dao-Yu, CHEN Sheng-Tang, ZHOU Ming

  2022,41(5):871-878, DOI: 10.11972/j.issn.1001-9014.2022.05.011

  Abstract: (6) HTML (8) PDF (1.15 MKB)(50)

  Abstract:

  Based on the GaAs process of Nanjing electronic devices institute， a 750~1 100 GHz tripler and a low loss 1 030 GHz sub-harmonic mixer have been completed. To improve the performance of the module， the parameter optimization of the device is introduced in the traditional design method of field circuit combination， and the mutual feedback relationship is established. Therefore， the whole design process establishes the closed-loop. The 3 μm thick monolithic circuit is supported in the cavity structure by using beam lead. The measured result shows that the output power of the broadband frequency multiplier is -23 ~ -11 dBm in the frequency range of 790~1 100 GHz. Using the above-mentioned frequency multiplier source as the RF signal to test the sub-harmonic mixer， the conversion loss is better than 17.5 dB in the frequency range of 1 020 ~ 1 044 GHz， and the minimum conversion loss is 14.5 dB at 1 030 GHz.

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Infrared Spectroscopy and Spectral Analysis

• Detection of oxygen residual concentration in medicine glass vials based on peak width correction

  SHEN Shuai, HE Jian-Jun

  2022,41(5):879-887, DOI: 10.11972/j.issn.1001-9014.2022.05.012

  Abstract: (13) HTML (3) PDF (1.96 MKB)(45)

  Abstract:

  The oxygen residue in the glass medicine vial poses a serious threat to the sterility of the medicine in the vial. In this paper， the peak height of the second harmonic signal demodulated by the wavelength modulated spectrum （WMS） technology is used as the basis of oxygen concentration inversion. However， when measuring gas concentration with second harmonic signal， the change of modulation depth will lead to the change of second harmonic peak， which will usually bring errors to the system and reduce the inversion accuracy of concentration. However， the modulation depth is affected by the fluctuation of modulation current， temperature and pressure， and cannot be calculated directly. To solve this problem， we first successfully convert the relationship between modulation depth and secondary harmonic peak height into the relationship between secondary harmonic peak width and peak height. Then， the gas concentration is inversed by using the harmonic peak height after being corrected by peak width. Preliminary experiments show that when using the harmonic peak height after peak width correction to predict the gas concentration in the vial， not only the accuracy of the system is improved by 2.1%， but also the overall robustness of the system is improved.

• On-site determination of optical constants for thin films

  XIE Mao-Bin, WU Zhi-Yong, CUI Heng-Yi, ZHAO Xin-Chao, XUAN Zhi-Yi, LIU Qing-Quan, LIU Feng, SUN Liao-Xin, WANG Shao-Wei

  2022,41(5):888-893, DOI: 10.11972/j.issn.1001-9014.2022.05.013

  Abstract: (8) HTML (4) PDF (748.77 KKB)(43)

  Abstract:

  The optical constants （refractive index and extinction coefficient） accuracy of thin films directly affects the properties of designed and fabricated optical devices. Most of the determination methods of optical constants are complex and cannot be applied during the film depositing process. In this paper， an optical constants determination method of thin films on-site is proposed. By monitoring the transmittance of depositing materials， this method can rapidly and accurately determine the optical constants on-site. For demonstration， the near-infrared optical constants of high-absorption material Si， low-absorption material Ta₂O₅ and ultra-low-absorption material SiO₂ are obtained as n=3.22， k=4.6×10^-3， n=2.06， k=1.3×10^-3 and n= 1.46， k=6.6×10^-5 respectively by this method. It reveals that this method is suitable for determining both strong and weak absorption materials’ optical constants. It provides an effective way for precisely determining optical constants on-site， which is meaningful for the design and fabrication of high-quality optical devices.

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Remote Sensing Technology and Application

• Prediction of independent sea ice motion in Arctic channel based on Multiloss-SAM-ConvLSTM

  ZHENG Fu-Qiang, KUANG Ding-Bo, HU Yong, GONG Cai-Lan, HUANG Shuo

  2022,41(5):894-904, DOI: 10.11972/j.issn.1001-9014.2022.05.014

  Abstract: (23) HTML (9) PDF (1.23 MKB)(52)

  Abstract:

  Accurate prediction of independent sea ice motion in arctic shipping lanes is of great guiding significance for ensuring navigation safety， assessing navigation navigability and dynamically correcting shipping lanes. However， the traditional optical flow method cannot meet the requirement of "spatio-temporal prediction + semantic segmentation". In this paper， the sea ice motion data set SeaiceMoving was made based on MERSI-Ⅱ image and a sea ice motion prediction algorithm based on Multiloss-SAM-ConvLSTM was proposed， introducing weighted FDWloss based on SAM-ConvLSTM to enhance the acquisition of spatial semantics of each node. Aiming at the imbalanced sample distribution， we discussed the offset effect of back-end segmentation threshold. The optimal segmentation threshold is determined by grid search method， which improves the overall prediction result of sea ice motion. The experimental results indicate that the Kappa coefficient， IOU coefficient and Dice coefficient of the proposed method are 0.75， 0.61 and 0.76 respectively. Compared with SAM-ConvLSTM， they are improved by 0.1， 0.12 and 0.1 respectively. Furthermore， the proposed method can improve the position prediction and shape recovery ability of sea ice after motion and reduce the "adhesion" of sea ice. In addition， the algorithm can still effectively predict the sea ice motion under the interference of thin clouds， which can provide more accurate technical support for the dynamic planning and route correction of the Arctic route.

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Infrared Photoelectric Technology and Application

• Satellite laser ranging research based on near-infrared low-power laser

  GAO Tian-Quan, WU Xian-Lin, ZHANG Cai-Shi, ZHOU Li-Xiang, ZHAO Hong-Chao, HAN Xi-Da, LIU Sheng-Qian, LI Ming

  2022,41(5):905-913, DOI: 10.11972/j.issn.1001-9014.2022.05.015

  Abstract: (17) HTML (7) PDF (1.95 MKB)(55)

  Abstract:

  In order to analyze the satellite laser ranging （SLR） detection capability of the TianQin Laser Ranging Station， the laser energy （average power） is set as 0.15 mJ （0.015 W）， 0.4 mJ （0.04 W） and 4 mJ （0.4 W）， respectively， to conduct laser ranging experiments on synchronous orbit satellites qzs2， compass i3 and compass i5 at night and daytime. Theoretically， the background noise of daytime skylight is analyzed， the effective echo rate of SLR under different average power conditions is calculated. Finally the impact of average power on SLR detection capability is particularly analyzed. In the experiment， the pitch angle of the telescope is fixed （E=50°）， and the skylight background noise intensity is measured by rotating the telescope at different points. A superconducting nanowire single photon detector （SNSPD） with a detection efficiency of 60% （@1064 nm） is used， and background noise is suppressed by spatial filtering， temporal filtering and spectral filtering. Using 0.4 mJ （0.04 W） energy to perform laser ranging on the synchronous satellite in the daytime. Using 0.15 mJ （0.015 W） energy to perform laser ranging on the synchronous satellite at night. The Tianqin Laser Ranging Station has the capability of conventional SLR throughout the day and night， which will lay the foundation for the full-time laser ranging of the Tianqin plan gravitational wave detection satellite in the future.

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• An ultra-efficient streaming-based FPGA accelerator for infrared target detection

  CHEN Shao-Yi, TANG Xin-Yi, WANG Jian, HUANG Jing-Si, LI Zheng

  2022,41(5):914-922, DOI: 10.11972/j.issn.1001-9014.2022.05.016

  Abstract: (20) HTML (8) PDF (2.67 MKB)(64)

  Abstract:

  Object detection algorithm based on deep learning has achieved great success， significantly better than the effect of traditional algorithms， and even surpassed human in many scenarios. Unlike RGB cameras， infrared cameras can see objects even in the dark， which can be used in many fields like surveillance and autonomous driving. In this paper， a lightweight target detection algorithm for embedded devices is proposed， which is accelerated and deployed using Xilinx Ultrascale+MPSoC FPGA ZU3EG. The accelerator runs at a 350 MHz frequency clock with throughput of 551 FPS and power of only 8.4 W. The intersection over union （IoU） of the algorithm achieves an accuracy of 73.6% on FILR datasets. Comparing with the previous work， the accelerator design improves performance by 2.59× and reduces 49.02% of the power consumption.

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• A study on a method to achieve large dynamic range readout of infrared detectors with a single gain

  WANG Hong-Yi, ZHANG Si-Tao, WANG Xu-Quan, ZHANG Yong-Gang, HUANG Song-Lei, FANG Jia-Xiong

  2022,41(5):923-929, DOI: 10.11972/j.issn.1001-9014.2022.05.017

  Abstract: (12) HTML (7) PDF (895.78 KKB)(63)

  Abstract:

  The current infrared detectors are difficult to achieve their own dynamic range by primary integration using traditional readout methods. In order to achieve large dynamic range readout of infrared detectors without changing gears， this paper introduces Pulse Frequency Modulation （PFM） and adopts the CTIA input stage structure to ensure the injection efficiency when the signal is weak， and investigates the method of large dynamic range readout of infrared detectors without changing gears. A CTIA input-level pulse frequency modulation （PFM） readout method was proposed to build an experimental system at the system level and conducted digital quantization experiments with short-wave infrared InGaAs cell detectors. The conversion linearity problem caused by the delay time of system structure at strong signal was analyzed in detail， and a digital quantization conversion model under non-ideal conditions was established. The experimental results show that the dynamic range of the proposed CTIA input stage PFM IR detector readout method reaches 97 dB， which provides a feasible solution for large dynamic range readout of IR detectors without changing gears， and lays a theoretical foundation for digital readout circuit design.

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Image Processing and Software Simulation

• Infrared image dehazing based on hierarchical subdivision superpixels and information integrity prior

  LI Wei-Hua, LI Fan-Ming, MIAO Zhuang, TAN Chang, MU Jing

  2022,41(5):930-940, DOI: 10.11972/j.issn.1001-9014.2022.05.018

  Abstract: (21) HTML (8) PDF (5.30 MKB)(68)

  Abstract:

  Hazy weather degrades the contrast and visual quality of infrared imaging systems due to the presence of suspended particles. Most existing dehazing methods focus on enhancing global contrast or exploit a local grid transmission estimation strategy on images， which may lead to loss of information， halo artifacts and distortion in sky region. To address these problems， a novel single image dehazing model based on superpixel structure decomposition and information integrity protection is proposed. In this model， based on the local structure information， the image is first adaptively divided into multiple objective regions using a hierarchical superpixel algorithm to eliminate halo artifacts. Meanwhile， to avoid the error estimate caused by the local highlighted targets， a modified quadtree subdivision based on superpixel blocks is applied to obtain the global atmospheric light. Furthermore， a combined constraint is used to optimize the transmission map by minimizing the loss of information. Compared with state-of-the-art methods in terms of qualitative and quantitative analysis， experiments on real-world hazy infrared images demonstrate the efficacy of the proposed method in both contrast and visibility.

Volume 41,2022 Issue 5

图像处理及软件仿真

• Light-weight infrared small target detection combining cross-scale feature fusion with bottleneck attention module

  LIN Zai-Ping, LI Bo-Yang, LI Miao, WANG Long-Guang, WU Tian-Hao, LUO Yi-Hang, XIAO Chao, LI Ruo-Jing, An Wei

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (28) HTML (0) PDF (4.74 MKB)(36)

  Abstract:

  This paper proposed a light-weight single frame infrared small target detection network that combined cross-scale feature fusion and bottleneck attention module. Instead of bringing extra huge neurons， the network directly performs cross-scale feature interaction between the encoding and decoding sub-networks， maintain the response of small target in the deep CNN layers， and thus achieves the full fusion between the spatial structure features from shallow layers and high-level semantic features from deep layers. Based on cross-scale feature fusion module， a light-weight bottleneck attention module is introduced to further enhance the response the target feature in the deep layers of the network. Experimental results demonstrate that the network can effectively suppress the complex background clutter and achieve high performance of infrared small target detection with low amount of parameters.

红外材料与器件

• Failure modes and analysis for HgCdTe linear photoconductive detectors

  QIAO Hui, WANG Ni-Li, LAN Tian-Yi, ZHAO Shui-Ping, TIAN Qi-Zhi, LU Ye, WANG Reng, HUO Qin, SHI Fan, TANG Yi-Dan, CHU Kai-Hui, JIA Jia, ZHOU Qing, SUN Xiao-Yu, JIANG Pei-Lu, LUO Yi, CHENG Xin-Yi, LI Xiang-Yang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (14) HTML (0) PDF (2.36 MKB)(30)

  Abstract:

  Failure modes during screening tests and application processes have been summed up for HgCdTe linear photoconductive detectors which have been applied in several programs. The mechanisms behand these failure modes have been analyzed based on the combination of HgCdTe material parameters， device structure dimensions， detector physics， fabrication processes and device test techniques. Criteria of failure modes have been firstly proposed for deeper understanding of HgCdTe linear photoconductive detector and better optimization of detector screening process， which are also helpful for the analysis and resolution of problems encountered in the application of HgCdTe linear photoconductive detectors.

• Switchable dual-wavelength vertical-external-cavity surface- emitting laser

  LI Xue, ZHANG Jj-Ye, ZHANG Jian-Wei, ZHANG Xing, ZHANG Zhuo, ZENG Yu-Gang, ZHANG Jun, ZHOU Yin-Li, ZHU Hong-Bo, NING Yong-Qiang, QIN Li, WANG Li-Jun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (123) HTML (0) PDF (901.14 KKB)(111)

  Abstract:

  This paper presents the design method and test results of a switchable dual-wavelength vertical-external-cavity surface-emitting laser （VECSEL）. The two lasing wavelengths with the separation of 50 nm are generated at different pumping powers using one single gain chip. During the operation of the VECSEL， the thermal rollover of output power is observed twice. The first rollover indicates the first switch of lasing wavelength， which is due to the temperature rise within the gain chip and its tuned gain spectrum. The maximum output power of each emitting wavelength exceeds 1.5 W at 0 °C. The lasing wavelength can be switched between 950 nm and 1000 nm with the change of pump power， and dual-wavelength emission with output power of more than1.5 W is demonstrated. We believe that this kind of switchable dual-wavelength VECSEL device has great application potential as dual-wavelength laser sources for providing technical support for mid-infrared radiation.

• Monolithic master oscillator high efficiency diode laser with nearly diffraction-limited narrowband emission and 10 W of optical output power

  DU Wei-Chuan, HE Lin-An, LI Yi, HE Yu-Wen, XIE Peng-Fei, ZHOU Kun, ZHANG Liang, LIU Sheng-Zhe, GAO Song-Xin, TANG Chun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (126) HTML (0) PDF (2.61 MKB)(112)

  Abstract:

  High-power semiconductor laser with nearly diffraction limited narrowband emission was designed and fabricated. The monolithic master oscillator power-amplifier （MOPA） diode laser consists of distributed Bragg gratings， a narrow ridge waveguide and a tapered amplifier. The ridge waveguide with length of 8 mm and width of 3 μm is used as the single-mode seed source. A tapered gain section with length of 7 mm and a full taper angle of 3.3° amplify the seed power. The fabricated device reach an output power of 10.3 W with a slow axis beam quality M² （1/e²） factor of 1.06 and an electro-optic efficiency of 50.5% . The spectral linewidth is 40 pm （3 dB）， and a central wavelength tuning range of 4 nm was realized by the integrated Bragg gratings micro heater.

红外及光电技术与应用

• The photon detection mode of photomultiplier tubes considering the pulse height distribution

  XIANG Yu-Yan, MA Yue, LI Song

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (39) HTML (0) PDF (2.73 MKB)(9)

  Abstract:

  Photomultiplier tubes （PMT） have unique advantages in photon-counting lidar applications due to its photon-level sensitivity and lack of photon detection dead time. However， the output pulse height of PMT responds to the single photon follows the gaussian random distribution， and there may produce pile up between different pulses. When using the fixed threshold method to identify the photon events， the traditional single photon model can not accurately describe the photon detection process of PMT. By analyzing the influence of PMT output pulse height distribution， pulse pile up and the amplitude of photon event identification threshold on the photon events detection probability， a new PMT photon detection theoretical model was built， and the mode was simplified according to the practical application scene. The applicability of the simplified model was verified by Monte Carlo simulation. The correlation characteristics of the new model in photon-counting ranging are analyzed. A photon-counting lidar system is built， compared with Geiger mode APD， the PMT photon detection model has a slight loss of photon detection probability， but it has a smaller ranging walking error and higher ranging accuracy in photon-counting ranging applications. The experiment also proves that the new model is more consistent with the photon event detection probability distribution of PMT than the traditional single photon detection model. The new model has important guiding significance for the system design and theoretical analysis of PMT photon-counting lidar.

红外材料与器件

• Performance test method of InGaAs near infrared detector for astronomical observation

  SUN Bai-Cheng, GUO Jie, XU Fang-Yu, FAN Ming-Guo, GONG Xiao-Xia, XIANG Yong-Sheng, LING Yun, ZHANG Yu-Chen

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (43) HTML (0) PDF (938.75 KKB)(39)

  Abstract:

  Based on the evaluation system of astronomical infrared detectors， the performance of two InGaAs NIR detectors， liquid nitrogen-cooled and thermoelectric-cooled， was tested using a modified "photon transfer curve" tests method. The measured value is 83 e^-， which is much higher than the nominal value of 15 e^-； the high and low conversion factors of NIRvana are 1.25 ADU/e^- and 0.097 ADU/e^-， respectively， and the readout noise is 105 e^- and 380 e^-； the measured value of dark current of NIRvana at the high conversion factor step is 415 e^-/s， which is about twice of the nominal value. The theoretical estimate of the signal electron number of the Yunnan Observatory two-meter ring telescope at 1.565 μm solar magnetic field measurement is about 8800 e^-， and the NIRvana-LN detector signal-to-noise ratio is 70 under the measured dark current of 4.06 e^-/s， image exposure time of 20 ms， and readout noise of 83.59 e^-.

图像处理及软件仿真

• GPNet：Lightweight infrared image target detection algorithm

  LI Xian-Guo, CAO Ming-Teng, LI Bin, LIU Yi, MIAO Chang-Yun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (59) HTML (0) PDF (5.67 MKB)(35)

  Abstract:

  A lightweight infrared image target detection algorithm GPNet is proposed to address the need for accurate and real-time target detection in resource-constrained infrared imaging systems. The feature extraction network is optimized using GhostNet， feature fusion is performed using an improved PANet， and a depth-separable convolution is used to replace the ordinary 3×3 convolution at specific locations to better extract multi-scale features and reduce the number of parameters. Experiments on public datasets show that the algorithm in this paper reduces the number of parameters by 81% and 42% compared with YOLOv4 and YOLOv5-m， respectively； the average mean accuracy is improved by 2.5% and the number of parameters is reduced by 51% compared with YOLOX-m； the number of parameters is 12.3 M and the detection time is 14 ms， which achieves a balance between detection accuracy and number of parameters.

红外材料与器件

• Growth and characterization of InAsP/InAsSb superlattices by Metal Organic Chemical Vapor Deposition for mid-wavelength detection

  HUAI Yun-Long, ZHU Hong, ZHU He, LIU Jia-Feng, LI Meng, LIU Zhen, HUANG Yong

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (62) HTML (0) PDF (2.00 MKB)(36)

  Abstract:

  “Ga-free” strain-balanced InAsP/InAsSb superlattices grown on InAs substrate by Metal Organic Chemical Vapor Deposition（MOCVD）was proposed and implemented to explore its feasibility as an infrared absorption material. First， the band gaps of InAsP/InAsSbsuperlattices were calculated by k·p method， and it was found that their cut-off wavelengthscover mid-wavelength infrared to long wave infrared region. Then， InAs_0.8P_0.2/InAs_0.7Sb_0.3 superlattices were chosen and grown on InAs substrate by MOCVD. XRD measurement shows that the lattice mismatches between the InAs substrate peak and 0^th order satellite peak of superlattices is only 61"， indicating strain balance condition is achieved. AFM test for surface morphology shows its root mean square roughness is only 0.4 nm for 5×5 μm² regions. The low-temperature PL spectra shows strong superlattice emission with peak located around 3.3 μm， which is closed to the design value. All the results indicate the feasibility and practicality of strain balanced InAsP/InAsSb superlattices grown by MOCVD for infrared detection.

遥感技术与应用

• Calibration method of relative linear deviation angle of polarization three-dimensional imager

  ZHANG Yue, ZHANG Xue-Min, LIU Yi, LI Xuan, ZHANG Su, YU Yue, JIAO Jianchao, SU Yun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (19) HTML (0) PDF (2.14 MKB)(32)

  Abstract:

  Based on introduction about principle of polarization three-dimensional image and components of four apertures polarization three-dimensional imager， the influence of four apertures relative polarization direction on polarization three-dimensional imaging accuracy was analyzed， to determine the accuracy requirements for four apertures relative polarization directions. The calibration method of relative polarization direction of four linear polarizers in four aperture lenses and calibration method of relative polarization direction of four apertures polarization three-dimensional imager was developed. The calibration device was built， and the relative polarization direction calibration was carried out in the laboratory. The calibration error of relative polarization directions of four linear polarizers in four aperture lenses was ±0.5 degrees. The calibration error of relative polarization direction of four apertures polarization three-dimensional imager was ±1 degree. Thus， the normal direction error of three-dimensional polarization inversion can be guaranteed to be -5.47%~5.80%，that would ensure high-quality imaging of four apertures polarization three-dimensional imager.

• A waveform matching-based method of improving laser footprint geolocation for GaoFen-7 spaceborne laser altimeter in mountainous areas

  WU Yu, WANG Heng, HAN Qi-Jin, LONG Xiao-Xiang, MA Yue, LI Qing-Peng, ZHAO Pu-Fan, LI Song

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (84) HTML (0) PDF (3.20 MKB)(41)

  Abstract:

  This paper proposed a geolocation method for laser footprints based on the waveform matching. Specifically， for a single laser footprint， the simulated waveform based on airborne lidar point cloud data as prior measurements was matched with the captured waveform of the Gaofen-7 SLA. Within a laser track， the correlation coefficient of the matching results in successive footprints was calculated to further estimate the laser pointing and ranging information and re-geolocate the laser footprints in mountainous areas. A study area （the Utah State in USA） with local airborne lidar data was selected to verify the proposed method. With the mean surface slope of approximately 20°， the elevation accuracy of GaoFen-7’s laser footprints were improved from （2.45±2.93） m to （0.27±0.61） m， which proved the effectiveness of the proposed method.

太赫兹与毫米波技术

• Design of 220GHz power amplifier based on 90nm InP HEMT process

  CHEN Yan, MENG Fan-Zhong, FANG Yuan, ZHANG Ao, GAO Jianjun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (50) HTML (0) PDF (1.58 MKB)(44)

  Abstract:

  Based on the 90 nm InP HEMT process， a 220 GHz power amplifier terahertz integrated circuit design （TMIC） is designed. The amplifier adopts the on-chip Wilkinson power divider structure to realize the power synthesis of two-way five stage common-source amplifiers. The on-wafer measurement results show that the average small signal gain of the power amplifier is 18 dB. The power test results show that the saturated output power of the power amplifier is better than15.8 mW from 210 GHz to 230 GHz， with a maximum output power of 20.9 mW at 223 GHz. The size of the TMIC chip is 2.18 mm×2.40 mm.

红外材料与器件

• Study on Molecular Beam Epitaxy of High indium InGaAs Films

  YANG Ying, WANG Hong-Zhen, FAN Liu-Yan, CHEN Ping-Ping, LIU Bo-Wen, HE Xun-Jun, GU Yi, MA Ying-Jie, LI Tao, SHAO Xiu-Mei, LI Xue

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (89) HTML (0) PDF (1.23 MKB)(44)

  Abstract:

  The effects of molecular beam epitaxy growth parameters on the properties of high indium InGaAs materials have been investigated in this paper. The growth temperature， V/III ratio and arsenic dimer of In_0.74Ga_0.26As materials were investigated and adjusted to optimize the peak intensity of the photo luminescence and X-ray diffraction measurements， as well as background carrier concentration and mobility. Results show that moderate growth temperatures and V/III ratios are needed for the growth to improve the lattice quality， reduce the non-radiation recombination and decrease the background impurity concentration. The In_0.74Ga_0.26As materials grown using As₂ dimer show better material quality than those using As₄ dimer. For the material grown at 570 ℃， As₂ dimer and V/III ratio of 18， relatively strong photo luminescence and X-ray diffraction peak intensity have been achieved. At room temperature and 77 K， the background carrier concentrations were 6.3×10¹⁴ cm^-3 and 4.0×10¹⁴ cm^-3， while the mobilities were 13 400 cm²/Vs and 45 160 cm²/Vs， respectively.

太赫兹与毫米波技术

• Design of high-frequency circuit for W-band CW sheet beam extended-interaction klystron

  JIN Qi, GENG Zhi-Hui, ZHANG Jian, ZHANG Rui, YANG Xiu-Dong, LIAO Yun-Feng, XU Shou-Xi

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (69) HTML (0) PDF (2.64 MKB)(29)

  Abstract:

  To solve the problem that W-band klystron is difficult to achieve CW （continuous wave） high power， we propose a W-band CW sheet beam extended-interaction klystron （EIK） high frequency circuit operating at TM₃₁-2π mode. A sheet electron beam with a voltage of 20 kV， a current of 0.65 A and the dimension of 2.5 mm×0.3 mm is used. The high frequency system adopts five dumbbell type five-gap cavities and the output system adopts symmetrical output waveguide. By optimizing high-frequency structural parameters， the simulation results of 3D PIC show that more than 1200 W power can be obtained at an input power of 0.2 W， and the electron efficiency and gain are 9.35% and 37.8 dB respectively. In terms of sensitivity and error stability of high-frequency parameters， TM₃₁ mode and TM₁₁ mode are compared and analyzed in detail.

红外及光电技术与应用

• Optimum designs of micro-resonator photonic crystal waveguides with gradually varied formations

  WU Li-Heng, WANG Ming-Hong

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (129) HTML (0) PDF (5.42 MKB)(53)

  Abstract:

  In order to design high quality single pass-band wavelength channels， three types of micro-resonator photonic crystal waveguides with gradually varied formations are designed. Power transmission spectra of these waveguides are studied by using FDTD （Finite-Difference Time-Domain） method. The output performances of these structures are compared and analyzed by collecting the pass-bands parameters of power spectra. As the central rod radius value of the micro-resonator increases， single pass-band transmission patterns of every waveguide output show the law of three times regular periodic variations from the short wavelength to the long wavelength. Optimization of structural choices and structural parameter designs have favourable effects on the output performances， so all of these waveguides have promising potentials to develop more single pass-band wavelength channels. The results show that the optimized structures can possess high quality of single pass-band wavelength transmission characteristics， such as regular periodic variation patterns， favorable signal enhancement designs， stable transmission performances， excellent adaptability of broad bandwidth. The best type of the structural designs can be flexibly selected according to the required wavelength， and these waveguides have application values in the designs of dense optical communication system， integrated optical path， compact optical sensing interface etc.

• Research on imaging model of infrared camera with focal plane detector and its MTF measuring method

  KONG Jian, FU Yu-Tian, ZHAO Yue-Jin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (63) HTML (0) PDF (2.35 MKB)(39)

  Abstract:

  Imaging Model in space domain and frequency domain of an infrared camera with focal plane detector is established. It shows that because of the existence of back ground radiance and non-uniformity the geometrical performance of an infrared camera can be evaluated by MTF only when the camera is well-corrected and the linearity and space invariance condition is satisfied. An MTF measurement method of an infrared camera using focal plane detector is given. This method does not depend on the well correction of the camera and can avoid the deviation from the background radiance.

红外材料与器件

• High speed uncooled MWIR infrared HgCdTe photodetector based on graded bandgap structure

  SANG Mao-Sheng, XU Guo-Qing, QIAO Hui, LI Xiang-Yang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (56) HTML (0) PDF (2.23 MKB)(46)

  Abstract:

  We reported a high-speed room-temperature mid-wave infrared HgCdTe photodetector based on graded bandgap structure. This study explores a n-on-p homojunction structure on epitaxial HgCdTe， which achieves a total response time of 1.33 ns （750 MHz） under zero bias voltage at 300 K， which is faster than commercial uncooled MCT photovoltaic photodetectors and MWIR HgCdTe APDs under high reverse bias. The analysis based on one-dimensional equations shows that compositional grading in the absorber layer can form built-in electric field and the transport mechanism of carriers is changed， the model is confirmed by the comparisons of different graded HgCdTe photodetectors. Thereby， this work facilitates design of the high-speed HgCdTe MWIR detectors， and provides a promising method to optimize the ultrafast MWIR infrared photodetectors.

• Study on HgCdTe APD focal plane technology

  LI Xiong-Jun, ZHANG Ying-Xu, CHEN Xiao, LI Li-Hua, ZHAO Peng, YANG Zhen-Yu, YANG Dong, JIANG Wei-bo, YANG Peng-wei, KONG Jin-Cheng, ZHAO Jun, JI Rong-Bin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (104) HTML (0) PDF (5.03 MKB)(104)

  Abstract:

  A 256×256 HgCdTe APD hybrid focal plane array （FPA） with 30μm pixel pitch was prepared by B ion implantation n-on-p planar junction technology based on MW HgCdTe material grown by LPE. The performance parameters such as gain， dark current and noise factor were characterized and analyzed at liquid nitrogen temperature. The results show that the average gain of HgCdTe APD focal plane chip is 166.8 and the gain non-uniformity is 3.33% under - 8.5V reverse bias； Under 0 ~ - 8.5V reverse bias， the gain normalized dark current of APD device is 9.0×10^-14A~1.6×10^-13A， the noise factor F is between 1.0 and 1.5. In addition， the imaging demonstration of HgCdTe APD focal plane is carried out， and a good imaging effect is obtained.

• Design considerations to increase the power-efficiency of a supper-large-optical-cavity waveguide structure diode laser

  ZHOU Kun, HE Lin-An, Li Yi, HE Yu-Wen, DU Wei-Chuan, LIU Sheng-Zhe, ZHANG Liang, HU Yao, SONG Liang, GAO Song-Xin, TANG Chun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (69) HTML (0) PDF (2.49 MKB)(47)

  Abstract:

  The considerations in the epitaxial and longitudinal design of a supper-large-optical-cavity structure diode laser in the 976-nm band are numerically studied and presented here. Mode control layers were designed underneath and up the quantum well layer to suppress the lasing of high-order transverse modes. The electron leakage was suppressed by a band energy engineering， where the electron barrier increases from the p-waveguide layer to the p-cladding layer. The optimized structure has an internal loss of 0.66 cm^-1， an internal quantum efficiency of 0.954， and a full width at half maximum vertical far-field angle of 17.4°. For the resonant cavity design， a liner current profile along the cavity was proposed to reduce the longitudinal spatial hole burning effect， where a power penalty of 1.0 W at 20 A is suppressed. The 4-mm-long and 100 μm wide broad-area single emitter with the supper-large-optical-cavity epitaxial structure was designed to have a high power-efficiency of about 71% at an output power of 21 W under continuous current injection at 25°C.

• Quantum well modulated optical pumped vertical external cavity surface-emitting laser for dual-wavelength generation

  LI Zhi-Wei, ZHANG Zhuo, ZHANG Jian-Wei, ZHANG Xing, ZHOU Yin-Li, ZENG Yu-Gang, Ning Yong-Qiang, WANG Li-Jun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (58) HTML (0) PDF (2.02 MKB)(51)

  Abstract:

  Optically pumped dual-wavelength vertical external cavity surface-emitting semiconductor laser （VECSEL） with a single gain chip is reported. The active region of the gain chip is composed of two groups of quantum wells with different lasing wavelengths， one group of quantum wells with shorter wavelength operates by absorption pumping， and the other group of quantum wells with longer wavelength operates by in-well pumping. When the VECSEL is operating， the short-wavelength quantum wells pumped by the absorption region are first lased， due to the intensity modulation effect of the long-wavelength quantum wells on the short-wavelength quantum wells， it can be observed that the peak intensity of the spectrum oscillates periodically with time， pulsed operation of the VECSEL was observed by the highly sensitive detector. With the increasing of the pump power， stable dual-wavelength emission was achieved， the peak positions of emission wavelength are 967.5 nm and 969.8 nm respectively. The output power of the stable dual-wavelength emission can reach 560 mW， and the far fields show Gaussian cross-sections in orthogonal dimensions， and the divergence angles of 6.68° and 6.87° are obtained.

• Photoconductive focal plane arrays infrared detector based on PbSe

  CHEN Yan-Song, REN Zi-Yang, XU Han-Lun, ZHU Hai-Ming, WANG Yao, WU Hui-Zhen

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (123) HTML (0) PDF (1.81 MKB)(106)

  Abstract:

  The influence of the parameters of PbSe photoconductive infrared detector on the photoelectric response was simulated by the continuity equation of semiconductor non-equilibrium carriers. A small-scale pixel x-y addressable PbSe photoconductive focal plane array （FPA） detector was developed experimentally. The pixel size was 500 μm×500 μm， and the pixel pitch was 500 μm. The photoelectric response performance of the pixels of the PbSe FPA detector was experimentally characterized， and the effective pixel rate reached 100%. Under 500 K temperature blackbody radiation and 3.0 V bias voltage， the average responsivity and detectivity reached 110 mA/W and 5.5×10⁹ cmHz^1/2W^-1， respectively. The noise equivalent temperature difference （NETD） of the pixels ranged from 15 to 81 mK， and the average noise equivalent temperature difference was 32 mK. Using a mid-wavelength infrared imaging device， the infrared thermal imaging of the PbSe FPA detector on the thermal radiation target of 350~450℃ was preliminarily demonstrated. This work lays the foundation for the subsequent development of high-density pixel PbSe FPA detectors.

• The magic of III-Vs

  ZHANG Yong-Gang, GU Yi, MA Ying-Jie, SHAO Xiu-Mei, LI Xue, GONG Hai-Mei, FANG Jia-Xiong

  DOI:

  Abstract: (43) HTML (0) PDF (1.94 MKB)(21)

  Abstract:

  III-V compound semiconductors have abundant features for various electronic， optoelectronic and photonic applications， all arise from variform magic combination of group III and group V elements formed binaries， resulting in ever-changing characteristics. In this paper， diversified ternaries， quaternaries and quinaries are presented geometrically based on the binaries of arsenide， phosphide and antimonide， mainly concerned of their bandgap， lattice constant and the lattice match domain on different substrates. The features of nitride and dilute nitride， bismide and dilute bismuth， as well as boride， are also discussed briefly. An overall observation of whole III-Vs may contribute to the comprehensive understanding of their latent capacity and sustainable development， along with a lot of challenges.

太赫兹与毫米波技术

• High-efficiency AlN/GaN MIS-HEMTs with SiNx insulator grown in-situ for millimeter wave applications

  CHEN Xiao-Juan, ZHANG Yi-Chuan, ZHANG Shen, LI YAN-KUI, NIU Jie-Bin, HUANG Sen, MA Xiao-Hua, ZHANG Jin-Cheng, WEI Ke

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (30) HTML (0) PDF (1.99 MKB)(7)

  Abstract:

  In this work， high-efficiency AlN/GaN metal-insulator-semiconductor high electron mobility transistors （MIS-HEMTs） have been fabricated for millimeter wave applications. A 5-nm SiN_x insulator is grown in-situ as the gate insulator by metal-organic chemical vapor deposition （MOCVD）， contributing to remarkably suppressed gate leakage， interface state density and current collapse. The fabricated MIS-HEMTs exhibit a maximum drain current of 2.2 A/mm at V_GS=2 V， an extrinsic peak G_m of 509 mS/mm， and a reverse Schottky gate leakage current of 4.7×10^-6 A/mm when V_GS = -30 V. Based on a 0.15 um T-shaped gate technology， an f_T of 98 GHz and f_MAX of 165 GHz were obtained on the SiN/AlN/GaN MIS-HEMTs. Large signal measurement shows that， in a continuous-wave mode， the MIS-HEMTs deliver an output power density （P_out） of 2.3 W/mm associated with a power-added efficiency （PAE） of 45.2 % at 40 GHz， and a P_out （PAE） of 5.2 W/mm （42.2%） when V_DS was further increased to 15 V.

遥感技术与应用

• Efficient information acquisition spectral imaging system based on multi-field slits

  Liu Shi-Jie, Zhang Xing-Yu, Zhou Hao, Li Chun-Lai, Li Dong Jing, Qi Hong-Xing, Wang Jian-Yu

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (47) HTML (0) PDF (3.37 MKB)(8)

  Abstract:

  Video spectral imaging technology is an important direction in the development of remote sensing detection. It can achieve 4-dimensional information acquisition （two-dimensional space + spectrum + time）， which is of great significance for application such as dynamic target detection. The current technical means are mainly based on the filter method， and do not have the high-resolution advantage of grating. Uncoupled Slit Array Scan Hyperspectral imager （uSASHI） and Coded Slit Array Scan Hyperspectral imager （cSASHI） are proposed in this paper， both use multiple slits to achieve simultaneous acquisition of multiple fields of view information to improve the information acquisition rate， and enables video-level spectral imaging. The information obtained by each slit of uSASHI will not be coupled， and n slits can achieve n times the improvement of information acquisition efficiency. The slits of cSASHI are arranged according to the compressed sensing theory， which can achieve under-sampling conditions （sampling rate α≤ 1） video spectral imaging， the information acquisition efficiency can be improved by n/α times. The system designed in this paper finally realizes the 1024*490*30 spectral data cube 10Hz video spectral imaging method， and cSASHI achieves a higher frame rate. The proposed system provides a new direction for the video spectral imaging technology and lays a better foundation for future applications.

红外及光电技术与应用

• Effects of incident spectrum and radiative power density on the performance of GaSb thermophotovoltaic cell

  WANG Xin, CHEN Xue, PAN Hong-Yu, LIU Xiu-Li, XIA Xin-Lin

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (10) HTML (0) PDF (1.41 MKB)(5)

  Abstract:

  Thermophotovoltaics perform the characteristics of high efficiency， high power intensity and wide range of heat sources. To further enhance its energy conversion performance， the physical mechanism of opt-electrical conversion and its influence factors need to be detailly analyzed. Therefore， based on the spectral opt-electrical conversion process in the thermophotovoltaic cell， the microscopic carrier transport model in the cell is established. The coupled opt-electrical model is used for the simulation of GaSb thermophotovoltaic cell to explore the effects of spectral characteristics and power intensity of the incident radiation on the cell performance. The results show that under the fixed incident radiation power intensity， the energy conversion efficiency of the cell shows obvious non-monotonicity with the change of wavelength and the peak appears at 1.42 μm. In addition， under the fixed wavelength， with the rise of radiation power intensity， the maximum electrical output power intensity accordingly increases while the rise of the energy conversion efficiency gradually slows down. At 1.42 μm， the rise of the energy conversion efficiency reach the maximum about 4.85%.

遥感技术与应用

• A new method for LOS path planning and overlap rate setting of airborne area-array whisk-broom imaging

  WANG Chong-Ru, HANG Gui-Cheng, JIN Xiang-Bo, LIU Jun, ZHOU Cheng-Lin, WANG Yue-Ming

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (24) HTML (0) PDF (1.17 MKB)(5)

  Abstract:

  Airborne area array whisk-broom imaging systems require a high enough overlap rate between frames to avoid missed scans caused by the control error of the line of sight（LOS） during the scanning process， which restricts the imaging system"s adaptability under conditions of high speed height ratio， and limits the imaging swath of the system. This paper proposes a new method of LOS path planning model and overlap rate calculation. The scanning path of the LOS of the imaging system is optimal designed through the geometric analysis method of the image spherical projection， and based on the azimuth rotation angle of the image plane projection in the image sphere， a A new model for overlap rate calculation is developed. Theoretical analysis and simulation experiments have verified that the stabilization accuracy of the LOS is increased from 2.93° to 0.15° when the lateral gaze imaging is performed at 40°， and the operation efficiency is increased by about 32% when the same speed height ratio and single-line 5-frame whisk-broom imaging are performed. The research work of this thesis is of great significance to promote the further development of airborne whisk-broom imaging technology toward the direction of wide field of view， high speed height ratio， and high resolution.

太赫兹与毫米波技术

• Effect of a Planar Metamaterial on the efficiency improvement and parasitic oscillations suppression of a Meander-line Slow Wave Traveling Wave Tube

  LI Zhou-Qi-Jun, WEN Zheng, ZHANG Zhi-Qiang, LUO Ji-Run

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (43) HTML (0) PDF (1.61 MKB)(4)

  Abstract:

  An open rhombic metamaterial structure is proposed to suppress the parasitic mode oscillations and improve the beam-wave interaction efficiency of a U-shaped meander-line slow wave traveling wave tube. The effect of the metamaterial on the surface E-field enhancement of the beam-wave interaction and the suppression of the parasitic oscillations were discussed through the combination of the circuit design with the numerical simulation optimization by considering the resonant performance of the metamaterial unit， the coordination of the matamaterial with the slow wave structure， the realizability and simplicity of the circuit structure. The simulated results for a Ka-band U-shaped meander-line slow wave traveling wave tube show that this metamaterial is effective in suppressing the parasitic oscillations and improving beam-wave interaction efficiency， which is of great significance for improving the stability of this kind of traveling wave tube.

红外材料与器件

• Silicon-based C-band low-loss compact polarization splitter rotator based on PSO algorithm

  HUI Zhan-Qiang, LI Bin, LI Tian-Tian, HAN Dong-Dong, GONG Jia-Min

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (26) HTML (0) PDF (1.54 MKB)(7)

  Abstract:

  A compact polarization splitter rotator （PSR） based on the principle of mode evolution is proposed. The device consists of a tapered TM₀-TE₁ mode converter and a mode splitter with an asymmetric directional coupler （ADC） structure， optimized by particle swarm optimization （PSO） and the principle of spline interpolation. The device is simulated using the finite difference time domain method （FDTD）. The numerical results show： for TE₀ mode input， a low insertion loss （<0.007dB）， low crosstalk （<-28.7dB）， and high polarization extinction ratio （>49.1dB） in the 100nm （1500-1600nm） bandwidth is achieved within a device length of only 45μm. On the other hand， for TM₀ mode input， a low insertion loss （<0.34dB）， low crosstalk （<-47.1dB）， and high polarization extinction ratio （>15.5dB） in the whole C-band is achieved. The insertion loss value at 1550nm is reduced to 0.06dB. In addition， the tolerance of the device is analyzed and the results reveal that the proposed device is robust. The designed PSR has small loss， compact size， and low crosstalk， which are important for future applications in large-scale photonic integration.

太赫兹与毫米波技术

• Design of 230-250GHz low noise amplifier based on 70nm InP HEMT process

  LIU Xing, MENG Fan-Zhong, Chen Yan, ZHANG Ao, GAO Jian-Jun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (31) HTML (0) PDF (1.27 MKB)(8)

  Abstract:

  Based on the 70 nm InP HEMT process, a 230-250 GHz low noise amplifier terahertz Integrated circuit design (TMIC) is designed. The amplifier adopts cascade structure of five common-source amplifiers to achieve low noise amplification. Based on the bias network which consists of microstrip radial stub and transmission line to isolate RF signals and DC bias signals. The first and second stages of the amplifier are designed based on noise matching technology, the middle two stages are designed based on power matching technology, and the last stage focuses on output matching. The on-chip test results show that the small signal gain of the LNA is greater than 20 dB in the frequency range of 230~250 GHz. The Y-factor method is used to complete the noise test of the encapsulated low noise amplifier module. The noise figure of the MMIC amplifier is better than 7.5dB in the frequency range of 243~248 GHz. Compared with HBT and CMOS processes, the low noise amplifier based on HEMT process has a noise figure advantage of more than 3dB.

红外材料与器件

• Effect of polarity of CdZnTe substrate on slider liquid phase epitaxy of HgCdTe

  HUO Qin, ZHANG Cheng, JIAO Cui-Ling, WANG Reng, MAO Cheng-Ming, LU Ye, QIAO Hui, LI Xiang-Yang

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (18) HTML (0) PDF (867.00 KKB)(11)

  Abstract:

  The effect of CdZnTe substrates with different polarity （111） plane on slider liquid phase epitaxalgrowth of Hg_1-xCd_xTe was studied. The experimental results show that the composition and thickness of HgCdTe films grown by slider liquid phase epitaxy on （111）A surface CdZnTe substrate were equivalent to those on conventional （111）B surface CdZnTe substrate； the contact angles between HgCdTe melt and （111） A surface and （111） B surface of HgCdTe films grown on CdZnTe substrate were respectively 50±2° and 30±2°， and it is confirmed that the surface tension between HgCdTe melt and （111） A surface of HgCdTe film is larger combined with micro model analysis； the difference between the surface morphology of HgCdTe film grown on （111） A surface and that on （111） B surface was observed and discussed； the FWHM of the HgCdTe film grown on （111） A surface was 33.1 arcsec. The effect of （111） plane polarity on melt droplet is reported for the first time， and the results show that slider liquid phase epitaxy of Hg_1-xCd_xTe on （111） A surface CdZnTe substrate can greatly reduce melt droplet of the film without reducing the crystal quality.

红外及光电技术与应用

• High-efficiency nanolaser based on multipath positive feedback mechanism of matching zero-index metamaterials

  ZHANG Zhen-Qing, DONG Li-Juan, DENG Fu-Sheng, Li Yun-Hui, XU Jing-Ping, SUN Yong, CHEN Hong

  DOI:

  Abstract: (71) HTML (0) PDF (1.57 MKB)(50)

  Abstract:

  For the traditional Fabry-Perot cavity applied in Laser， the field perpendicular to cavity wall will be resonantly enhanced until it breaks through the threshold and escapes out of the cavity， while the field emitted obliquely dissipates outside the cavity leading to the low efficiency. Here a high-efficiency laser cavity is proposed resorting to metamaterials. Based on the multipath positive feedback mechanism， the photons emitted form atoms in any direction can only leak out of the cavity along one direction and no photons run out of the cavity which show potential in improving the efficiency. Furthermore， this combination of cavity is almost independent of atom position. In addition， we designed a realistic dielectric micro-structure system made of two-dimensional photonic crystals to confirm our proposal. When the gain medium is introduced in the system， the cavity can provide both a lower lasing threshold and a higher maximum emission intensity， compared with the individual zero-index materials cavity， demonstrating improved lasing efficiency.

太赫兹与毫米波技术

• Terahertz Sheet Beam Vacuum Electron Devices

  Lyu Zhifang, Zhang Changqing, Wang Zhanliang, Jiang Shengkun, Ruan Cunjun, Feng Jinjun, Gong Yubin, Duan Zhaoyun

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (90) HTML (0) PDF (1.32 MKB)(79)

  Abstract:

  Sheet beam is a kind of electron beam， whose cross-section is approximate rectangular or elliptical shape with high aspect ratio. Compared with conventional pencil beam， sheet beam has many advantages， such as high beam current and large interaction area. Terahertz science and technology have got rapid development in recent years owing to its high frequency， wide bandwidth， high-speed transmission rate， and other advantages of terahertz waves. As a kind of new-type vacuum electron devices， terahertz sheet beam devices have excellent performance such as high power， high gain， high efficiency， and miniaturization. However， it is difficult for sheet beam to keep stable transport over a long distance due to the existence of Diocotron instability， which cannot lead to fully demonstrating its technical advantages. This paper briefly summarizes the generation， formation， and focusing methods of sheet beam， and then introduces the state-of-the-art of terahertz sheet beam devices. Finally， the challenges and development tendencies are discussed.

图像处理及软件仿真

• Low power application specific SoC chip for uncooled infrared image processing

  GUO Guang-Hao, WU Nan-Jian, LIU Li-Yuan

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (86) HTML (0) PDF (1.64 MKB)(167)

  Abstract:

  Uncooled infrared imaging technology has a very broad application prospect. However， there are some urgent problems to be solved， such as non-uniformity correction， image detail enhancement and stripe noise. This paper proposes and designs a special SoC chip for image processing for uncooled infrared imaging. The chip integrates a CPU， two DSP processors and a special accelerator for infrared image processing. A single chip can realize real-time image processing such as non-uniformity correction， image filtering， histogram equalization， digital image detail enhancement， stripe elimination and target detection and tracking. At the same time， research and development of uncooled low-power infrared image processing algorithms for chip applications. The 65-nm CMOS process is used to realize the special processing SoC chip for uncooled infrared images， and a small and low-power uncooled infrared imaging system based on the uncooled infrared imaging chip and the image processing SoC chip is realized. The test results show that the imaging system can realize functions such as clear uncooled infrared imaging， target detection and target tracking. The power consumption of the system is less than 2 W， and the volume is reduced by 50% compared with the traditional system. It meets the application requirements of systems with high requirements for volume， power consumption and performance， and has high engineering application value and prospect.

• An Acousto-Optic Tunable Filter Spectral Measurement Method based on Compressed Sensing

  JI Zhong-Peng, GUI Yu-Hua, LI Jin-Ning, TAN Yong-Jian, YANG Qiu-Jie, WANG Jian-Yu

  DOI:

  Abstract: (98) HTML (0) PDF (901.64 KKB)(199)

  Abstract:

  Acousto-Optic Tunable Filter （AOTF） based spectroscopy instruments have been widely applied in biomedical， agricultural， aerospace， and other fields. However， the conventional AOTF spectrometers struggle to achieve increased system luminous flux while maintaining spectral resolution and reducing the number of samples. To address the above problems， this paper proposes an AOTF spectral measurement method based on the compressed sensing （CS） theory. Sparse randomly coded composite optical signal modulation in the spectral domain using the multi-frequency acousto-optic diffraction of AOTF. A modulated composite optical signal is obtained in the spectral domain and recorded sequentially using a single-element detector or a focal-plane detector array. The original spectrum or spectral image data cube is then obtained by using compressed sensing reconstruction algorithms. In order to verify the effectiveness of the present method， we constructed a sensing matrix using the actual measured AOTF spectral response bandwidth data and simulated the effect of compressed sampling and target data reconstruction with the spreading spectrum as the recovery target. The simulation results show that the method can reconstruct the spectral data of 512 wavelength points with 202 compressed samples， and the spectral data sampling rate and compression ratio is 0.39. Under this sampling rate， the method can recover the spectral curve with high accuracy， and the PSNR index reaches 41.75 dB， and the SAM and GSAM indexes are 0.9998 and 0.9754. With the simultaneous multi-frequency drive， the system optical throughput is improved by a factor of 5 on average. Compared with the traditional wavelength-by-wavelength point scan sampling method， this method can reduce the total number of samples and improve the luminous flux of the system while maintaining the original spectral resolution， and also compressing the spectral data， which is of great importance in the fields of weak signal detection， rapid identification of substances， and spectral data transmission and storage.

• Object detection based on polarization-weighted local contrast method

  ZHAO Yong-Qiang, ZHANG Jing-Cheng, QIAO Xin-Bo

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (129) HTML (0) PDF (1.48 MKB)(171)

  Abstract:

  The images captured by the division-of-focal-plane （DoFP） infrared polarimeters have checkboard effect. Thus， a polarization demosaicking processing of DoFP images is demanded to recover the full resolution polarization images， based on which， the subsequent tasks are then performed. However， the demosaicking processing is usually time-consuming and may introduce demosaicking errors. To achieve object detection by directly using infrared polarization DoFP image， a polarization-weighted local contrast object detection method is proposed. The difference of polarization characteristics between the object and background is first analyzed. Then， a convolution kernel is designed to calculate the Stokes vector directly from original infrared polarization DoFP images. A polarization-weighted saliency map of the degree of polarization image is also proposed， which is used for object detection with the adaptive thresholding. In addition， an edge detection method is used to refine the target detection results and obtain more complete detection results. The experiment results on the infrared polarization DoFP images dataset demonstrate that the proposed object detection algorithm is robust to the conditions of complex background and bad weather.

红外及光电技术与应用

• Multiblock compressed sensing imaging in real time

  LI Hu, LIU Xue-Feng, YAO Xu-Ri, LIU Fan, DOU Shen-Cheng, HU Tai, ZHAI Guang-Jie

  DOI:

  Abstract: (169) HTML (0) PDF (1.05 MKB)(253)

  Abstract:

  Imaging sensors in medium and long-wave infrared spectrum are extremely expensive. Therefore， for most consumers， remote high-resolution imaging and real-time display in these spectrums are still a challenge. This paper proposes an effective block compressed sensing method called Multi-block Combined Compressed Sensing （MBCS） adapting to Focal Plane Array Compressed Imaging system （FPA CI）， which combines parallel sampling and fast reconstruction. The high-resolution images can be reconstructed from low-resolution measurement results in real-time using a low-resolution infrared sensor. The results showed that， compared with the traditional CS-based super-resolution method， this method could greatly improve the quality of the reconstructed high-resolution image and achieve a higher reconstruction speed. The optical prototype architecture and construction of the MBCS measurement matrix for the reconstruction model are also discussed. This study evaluated the reconstruction performance in terms of the block size and found that the optimal block size needed to consider both speed and reconstruction quality. Furthermore， the MBCS reconstruction algorithm with GPU acceleration was implemented to improve the image reconstruction speed of the highly parallel image system. In the experiment， the optical system and the strategy of rapid imaging and reconstruction were verified via simulation and optical experiments， which showed that the imaging speed of 512×512 resolution could reach 5 Hz.

Infrared Materials and Devices

• Studies on the surface treatment of InAs/GaSb type-II super-lattice long-wave infrared detectors

  CUI yu-rong

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (688) HTML (0) PDF (0.00 ByteKB)(608)

  Abstract:

  In this work， the surface treatment of InAs/GaSb type-II super-lattice long-wavelength infrared detectors is studied. An optimizing process of N₂O plasma treatment and rapid thermal annealing was developed， which can improve the performance of long-wavelength detector with λ_{50% cut-off}=12.3μm from 5.88 ×10^-1A/cm² to 4.09 ×10^-2A/cm² at liquid nitrogen temperature， -0.05V bias. Through variable area device array characterization， the sidewall leakage current was extracted. Under zero bias， the surface resistivity improved from 17.9Ωcm to 297.6 Ωcm. However， the sidewall leakage couldn’t be ignored under large inverse bias after optimizing process， where surface charge might induce the surface tunneling current. It is verified by gate-control structure that there are two main leakage mechanisms in long-wave device： pure sidewall parallel resistance and surface tunneling. At last， the surface charge was calculated to be 3.72×10¹¹cm^-2 by IV curve fitting after optimizing process.

红外材料与器件

• Regulation on Microstructural and Optical Properties of Sb2Te3 Films Induced by Titanium Doping

  LIAO Yuan-Jie, Li Yao-Peng, SONG Xiao-Xiao, ZHANG Xin-Tong, ZHANG Shu-Bo, ZHANG Teng-Fei, LV Meng-Qi, LIU Zhen, ZOU Yi-Yun, ZHANG Ye, HU Er-Tao, LI Jing

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (27) HTML (0) PDF (0.00 ByteKB)(32)

  Abstract:

  In this work, the doping effects of Ti on the structural, linear optical properties and nonlinear absorption of Sb2Te3 thin films are systematically studied. A magnetron sputtering system and an annealing furnace are employed to prepare the crystalline Sb2Te3 samples with different doping concentrations of Ti. The X-ray photoelectron spectroscopy analysis confirmed that the Ti element exists in the Sb2Te3 films is in the form of TiTe2, in which the chemical state of Ti4+ arises. For linear optical properties, the results indicates that the Ti dopant can improve the transmittance of the Sb2Te3 films, when a wide working wavelength is used in the nonlinear devices. The optical band gap decreases from 1.32 eV to 1.25 eV for the Ti-doped Sb2Te3 films, which is dependent on the reduction of carriers according to the Burstein-Moss theory. An open-aperture Z-scan system is set up to determine the nonlinear saturated absorption of the film samples, which is excited by an 800 nm femtosecond laser at a power of 132 GW/cm2. Moreover, the adjustable behavior caused by Ti doping could be attributed to the competition between the decrease in the optical band gap and the inhibition of the crystallization. Additionally, it is interesting to find that the Ti doping improves the laser damage threshold of the Sb2Te3 thin films from 188.6 to 265.5 GW/cm2. In general, the Ti-doped Sb2Te3 thin films have wide-ranging application possibilities for the field of nonlinear optical devices.

太赫兹与毫米波技术

• Theoretical Study and PIC Simulation of a 220GHz Gyro-TWT with Periodic Dielectric Loaded Waveguide

  CHEN Ru-Tai, Yu Sheng

  DOI: 10.11972/j.issn.1001-9014.XXXX.XX.001

  Abstract: (26) HTML (0) PDF (0.00 ByteKB)(33)

  Abstract:

  Gyrotron traveling wave tube (Gyro-TWT) as a high power and wideband amplifier, is one of the most attractive millimeter radiation sources and developing toward to higher frequency band (>100GHz). In this article, a 220GHz gyro-TWT operating at fundamental harmonic TE01 mode with periodic dielectric loaded (PDL) waveguide is designed through theoretical study and particle in cell (PIC) simulation. The parasitic oscillations (absolute instability oscillation and backward wave oscillation) have been successfully suppressed by study of start-up thresholds and loading dielectric rings. The beam wave interaction behaviors are compared between nonlinear theory programs and PIC simulation, the results are basically consistent. In PIC simulation, the optimized gyro-TWT was developed with saturated output power of 55.61kW, corresponding efficiency of 26.48% at 220GHz with 70kV and 3A electron beam, the saturated gain is 53.56dB, and -3dB bandwidth is 12GHz.

• On the Design of High Conversion Efficiency Quasi-Optical Mode Converter for 140GHz High-power Gyrotron Applications

  JinMing, Wang Dan-Yang, Zhang Yi-Chi, Han Yu-Nan, Bai Ming

  Abstract: (0) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  A high conversion efficiency quasi-optical mode converter prototype is designed for 140GHz TE22,6 applications. The Denisov launcher is designed based on the periodic perturbation concept, leading to primary radiation field with low edge diffraction. Full-vector physical optics integration solver is used to model and analysis the 3-mirror system. And the 3-step iterative phase correction is applied based on the co-polarization field component, so as to achieve high-quality mode conversion. Specifically, the correction of the 1st mirror sufficiently refines the non-ideal radiated fields from the launcher. It is then validated by numerical investigations that, comparing to the original quaritic mirrors, the phase-shaped mirror system leads to excellent conversion performance: The Gaussian content (ηv) of the output fields rises from 92.7% to 99.6%, while the power transmission efficiency (ηp) reaches 98.8%.

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• Laser Reflective Tomography Imaging Projection Registration Method based on Target Contour Auto-correction

  ZHANG Xin-Yuan, HU Yi-Hua, HAN Fei, SHI Liang, XU Shi-Long, CHEN You-Long, WANG Yi-Cheng

  Abstract: (0) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Laser reflective tomography imaging has a wide application prospect of space target remote sensing because its resolution is independent of distance. Before the reconstruction of the target image, the multi-angle echoes projection data need to be aligned with the rotation center of the target, which is the projection registration technique. This paper proposed a projection registration method based on the target contour auto-correction, and the experimental results show that the method is easy to implement on simple target since the registration center of rotation, can effectively reduce the number of laser pulses launch and detector receive random jitter caused by the interference, such as solved the problem of the fuzzy image, is a kind of LRTI multi-angle echoes registration of new ideas.

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• The THz image resolution enhancement algorithm based on PSF

  xiebin

  Abstract: (0) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In recent years, terahertz (THz) imaging technology has received increased attention owing to the promising imaging tools now available for nondestructive testing. However, theoretical models of THz imaging systems are yet to be developed. In this study, we proposed a comprehensive mathematical modeling and simulation theory for the THz imaging system. Gaussian beam distribution was used in the mathematical modeling of the point spread function (PSF). The target function was convolved using the PSF, and the analog transmission of THz images was realized. The PSF of the imaging system was calculated using the optical imaging method. Next, the image was deconvolution-enhanced using the PSF. The image restoration results revealed that the image resolution improved. The restored image contains more details.

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• A 33-170 GHz Cascode Amplifier Based on InP DHBT Technology

  WANG Bo-Wu, YU Wei-Hua, HOU Yan-Fei, YU Qin, SUN Yan, CHENG Wei, ZHOU Ming

  Abstract: (7) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In this paper, a wide band cascode power amplifier working at 33-170 GHz is designed, based on the 500 nm InP dual-heterojunction bipolar transistor (DHBT) process. Two pairs of parallel input and output stub lines can effectively expand the working bandwidth. The output coupling line compensates the high frequency transmission. The measured results show that the maximum gain of the amplifier is 11.98 dB at 115 GHz, the relative bandwidth is 134.98 %, the gain flatness is ±2 dB, the gain is better than 10 dB and the output power is better than 1 dBm in the operating bandwidth.

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• Head motion detection based on low resolution infrared array sensor

  CHEN Liang-Qin, ZENG Ming-Xuan, XU Zhi-Meng, CHEN Zhi-Zhang

  Abstract: (9) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  People easily get distracted or tired after long-duration actions such as driving and online classes, which can lead to accidents or poor efficiency. To detect such human behaviors, a head motion detection method based on low-resolution infrared array sensors is proposed with the protection of personal privacy. First, prominent areas of the human body are extracted based on image processing techniques. Then a 3D image fusion algorithm is developed to extract the change information in the spatiotemporal domain. Finally, an improved residual network is developed to achieve head motion classification. Ten head movements are designed for driving and online classroom scenarios. Experimental results show that in the detection range of 50cm to 100cm, our average recognition rate is 96.76%, and the processing speed is 9 frames per second, which is better than the existing state-of-the-art algorithms. The accuracy of the system is 93.7% when it is applied to the vehicle experiment.

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• Spaceborne photon counting lidar point cloud denoising method with adaptive mountain slope

  He Guang-Hui, Wang Hong, Zhang Yong-An, Fang Qiang

  Abstract: (25) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Spaceborne photon counting LIDAR is an active satellite remote sensing payload developed in recent years, which obtains ground information by actively emitting pulsed lasers and receiving echo point cloud data. At present ,ICESat-2/ATLAS currently utilizes single-photon detectors in remote sensing of forest vegetation, which greatly improves the accuracy of vegetation remote sensing. However, a large amount of noise will be generated in the process of receiving signals, and the signal to noise ratio is lower in complex mountainous land, which greatly affects the accurate extraction of vegetation point cloud signals. To solve this problem, a density clustering algorithm based on mountain slope is proposed in this paper. By analyzing the density of point cloud data and the terrain characteristics of forest targets, coarse denoising is performed by using the maximum density center search method, and then the slope angle is calculated based on the point cloud data to optimize density clustering to complete the data fine denoising. By classifying the extracted forest region signal, fitting the vegetation canopy profile and the surface profile, the results show that the proposed algorithm has a high accuracy in the extraction of vegetation photon signal, and the RMSE of the ground and canopy profile are 0.3588m and 3.7449m, respectively, which is more suitable for vegetation remote sensing point cloud data processing.

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• Band alignment engineering of bilayer WS2/Ga2O3 heterostructures with interface-dependent photoluminescence

  YANG Wan-Li, HUANG Tian-Tian, ZHANG Le-Peng, XU Pei-Ran, JIANG Cong, LI Tian-Xin, CHEN Zhi-Min, CHEN Xin, DAI Ning

  Abstract: (21) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Two-dimensional (2D) van der Waals heterostructures and interfaces are widely researched for their potential application in next generation sensing, thermal imaging and light communication systems. Here, we demonstrated the hetero-interface induced anomalous photoluminescence (PL) emissions in the vertical WS2/Ga2O3 heterostructures. The WS2/Ga2O3 hetero-interface varies type-II band structure and brings subsequent PL decline in the bottom WS2 monolayer contacted with Ga2O3 layer. Such hetero-interlayer coupling interaction between oxides and 2D layered transition metal dichalcogenides (TMDs) in the stacked heterostructures impacts interlayer interaction between the bottom WS2 monolayer and the upper WS2 monolayer in a WS2 bilayer, which leads to an anomalous PL enhancement in the bilayer WS2. Stacked hetero-interface will benefit for controlling the optical or electronic behavior and modulating energy band structures by customizing transformative 2D heterostructures used in next-generation nanoscale optoelectronic detectors and photodetectors.

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• Research on the adaptability of space environment about NbN superconducting SIS mixer for High Sensitivity Terahertz Detection Module

  Zhang Kun, YAO Ming, LIU Dong, LIU Bo-Liang, LI Jing, Yao Qi-Jun, SHI Sheng-Cai

  Abstract: (21) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The High Sensitivity Terahertz Detection Module (HSTDM) is one of the scientific instruments of the China Sky Survey Telescope. HSTDM is a high-resolution spectrometer and the first space heterodyne receiver using niobium nitride (NbN)-based superconducting tunnel junction (Superconductor - Insulator - Superconductor (SIS)) mixer (the NbN SIS mixer). The NbN SIS mixer should meet the specification requested by a space environment, such as high operation reliability, robustness to vibration, cosmic irradiation, and thermal variation. This paper presents the space qualification tests performed on the NbN SIS mixer, including sine and random vibration tests, single-particle irradiation test, total dose radiation test, and thermal cycling test. The mixer’s performance analysis confirms that it can meet the space application requirements of HSTDM.

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• The study of magneto-optical conductivity of monolayer MoS₂

  LI Yue, XIAO Yi-Ming, XU Wen

  Abstract: (33) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The longitudinal magneto-optical conductivity of monolayer molybdenum disulfide (ML-MoS2) have been theoretically investigated under the quantizing Landau levels induced by applied magnetic field and proximity-induced exchange interaction via using the random-phase approximation (RPA) dielectric function approach. The effects of the proximity-induced exchange interaction and magnetic field on the longitudinal magneto-optical conductivity are examined. There have two magneto-optical absorption peaks induced by the transitions processes within the conduction band in the Terahertz (THz) frequency range. The inter-band transitions between conduction and valence bands result in a series of magneto-optical absorption peaks in the visible frequency range. The results indicate that the magnetic field and proximity-induced exchange interaction could have important influence on the longitudinal magneto-optical conductivity of ML-MoS2 and it could be applied in promising magneto-optics devices for spintronics and valleytronics working in visible to THz frequency range.

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• Millimeter wave high scanning rate quad-beam leaky wave antenna based on spoof surface plasmon polaritons (SSPP)

  PENG Zhen, ZHAI Guo-Hua, HUANG Dai-Xin, REN Ji-Shan, GAO Jian-Jun

  Abstract: (13) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In order to enhance the multi-object detecting and tracking capability, a four-beam millimeter wave frequency scanning leaky wave antenna (LWA) based on spoof surface plasmon polaritons (SSPP) has been proposed. According to the theory of sinusoidally modulated reactance superposing surface (SMRSS), Quad-beam LWA is realized by etching periodical slots on the top surface of substrate integrated waveguide (SIW), and uniform slots etched on the bottom layer is used to eliminate the open-stopband effect. The measurement shows that the four beams can scan from -52° to 22° within the frequency band from 29 GHz to 30.2 GHz, achieving a total of 74° scanning range, and the beam scanning is up to 18°/%BW, which not only saves the spectrum source but improvs the multi-target detection efficiency.

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• Modeling and Analysis for Imaging Characteristics of Infrared Array-aperture Diffraction Optical System

  NIU Rui-Ze, QIAO Kai, ZHI Xi-Yang, GONG Jin-Nan, JIANG Shi-Kai, TIAN Chao

  Abstract: (14) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  This paper establishes the modulation transfer function (MTF) and signal-to-noise ratio (SNR) characterization models under the diffraction efficiency influence, considering the diffraction optical imaging mechanism. Then, the imaging characteristics analysis model of the infrared array-aperture diffraction optical system is built based on the three-dimensional Finite Difference Time Domain (FDTD) method. Finally, the effects of different working wavelengths, field of views and filling factors on the imaging characteristics of the primary lens are analyzed. The analysis results show that the diffraction efficiency, the MTF and SNR of infrared array-aperture diffraction optical system all have spectral and spatial variation characteristics, and they reduce with the decrease of the filling factor. When the filling factor of the primary lens is 0.6, the integral area of MTF decreases by 45.42% and the SNR decreases by 4.92dB compared with the ideal full aperture system. The established model can be used to characterize the imaging quality of infrared array-aperture diffraction optical system and provide reference for the design of the imaging system.

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• Temperature uniformity and thermal deformation analysis of the cathode with radiation heating in the magnetron injection electron gun

  YANG Ming-Zhe, WANG Xiao-Xia, FAN Yu, MENG Ming-Feng, YANG Chen, GAO Cha, LUO Ji-Run

  Abstract: (36) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Based on the development of a magnetron injection electron gun(MIG) for gyrotron oscillator operating at 140 GHz and with about a megawatt output power, the temperature homogeneity of the cathode and thermal deformation of the MIG were analyzed with ANSYS code. Under a improved temperature homogeneity of the cathode, the geometrical and electrical parameters have been adjusted and optimized to eliminate the effect of thermal deformation on beam trajectory. The simulated temperature of the cathode will compared with the tested one for evaluating the rationality of the simulation model, which may be helpful for the actual design.

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• 335 GHz unbalanced Schottky diode frequency tripler

  LI Yu-Hang, ZHANG De-Hai, MENG Jin, QI Lu-Wei

  Abstract: (25) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Based on the hybrid integration method, a 335 GHz unbalanced frequency tripler is designed with a symmetrical tapered gradient line matching structure. Under the condition of ensuring single-mode transmission, the matching structure can increase the matching effect while fixing the position of the diode, and improve the problem of the narrow 3 dB bandwidth of the high-frequency band multiplier. The measured results show that the output power of the frequency tripler is greater than 5 mW in the frequency range of 330-356 GHz. The maximum output power is 11.2 mW at a driving power of 220 mW. The solid-state terahertz local oscillator composed of it as the core device can drive the 670 GHz sub-harmonic mixer in the superheterodyne receiver.

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• Analysis and control of abnormal phenomena in HgCdTe surface treatment

  LIU Yanzhen, LI Shujie, ZHANG Yingxu, XIN Yonggang, LI Zhihua, LIN Yang, LI Xiongjun, QIN Qiang, JIANG Jun, GUO Jianhua

  Abstract: (28) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The surface treatment is the beginning of the manufacturing process of HgCdTe infrared detector chip, and its quality will directly affect the yield of the chip. The mechanisms of four typical surface anomalies in the HgCdTe surface treatment process were explored using metallographic microscope, scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) analysis methods, and the corresponding control measures are proposed. The water mark defect is triggered by oxygen absorption corrosion, and this defect can be controlled by rapidly drying the HgCdTe surface with a stable nitrogen gas flow. The staining is induced by the corrosive liquid unevenly diluted or contaminated by impurities such as water. To reduce the probability of staining, the contamination should be strictly avoided in the process, and the surface should be quickly rinsed after corrosion finish. The round spot originates from the adsorption of the cleaning solution at the material defect, which can be controlled via using isopropanol to soak the HgCdTe before drying. When toluene is in direct contact with HgCdTe, the surface roughness of HgCdTe will increase, thus this direct contact should be restricted.

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• Dual-tunable triple-band absorber based on bulk Dirac semimetal and vanadium dioxide

  HU Bao-Jing, HUANG Ming, DING Hong-Wei, HONG Su-Mei

  Abstract: (22) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In this paper, a dual-tunable triple-band absorber based on bulk Dirac semimetal (BDS) and vanadium dioxide (VO2) is proposed. The electromagnetic properties of the absorber were analyzed by the finite difference time domain method and equivalent circuit model (ECM). When the VO2 is in fully metallic state, the absorption spectrum of the dual-tunable absorber exhibits three obvious absorption peaks with the average absorptance is 98.64%. The resonant frequencies and absorptivity of the absorber can be dynamically controlled by adjusting the Fermi energies of BDS and the conductivities of VO2. Finally, the relationships between the absorptivity of the dual-tunable absorber and the different thicknesses of the BDS, VO2 and immediate dielectric layers are further discussed. This work provides potential applications in the designs of multi-band dual-tunable filters and absorbers.

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• Study on photoelectric characteristics of compositionally graded HgCdTe detector

  XU Guo-Qing, WANG Reng, CHEN Xin-Tian, CHU Kai-Hui, YANG Xiao-Yang, ZHANG Yan, LI Xiang-Yang

  Abstract: (14) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The junction is prepared at the high composition end of nonlinear composition region and linear composition region respectively, and the photoelectric performance of HgCdTe detector with component gradient is studied. It is found that the change of the normalized response spectrum and the responsivity with temperature is different between two samples. To calculate the built-in electric field of composition gradient in two sample at different temperatures, the results show that the built-in electric field generated by the linear composition distribution is 100V/cm ~ 200V/cm, while the built-in electric field generated by the nonlinear composition distribution makes the electric field on surface of the sample as high as 2000V/cm. The analysis indicates that the influence of the built-in electric field generated by composition gradient in the junction of the two samples on the movement of the minority carrier is the main reason for the difference of the photoelectric performance with temperature, and the built-in electric field generated by the nonlinear composition distribution changing with temperature makes the responsivity of the sample show three different trends. Through the analysis of response spectrum and responsivity with different temperatures, it is shown that using the built-in electric field generated by the nonlinear composition distribution which is controlled by temperature can reduce the concentration of photogenerated carriers in the junction region and increase the hole drift speed in the junction region, which is conducive to reducing space charge effect and provides a new design idea for improving the saturation threshold of HgCdTe detector under large injection.

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• Study on terahertz spectral properties of pores in glass fiber composites

  XU Tuo, LU Xing-Xing, SHEN Yan, ZHANG Jin-Bo, CHANG Tian-Ying, CUI Hong-Liang, ZHANG Jin

  Abstract: (24) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The interaction mechanism between terahertz wave and pore defect in glass fiber composites is explored, and the interaction relationship between porosity and terahertz characteristic parameters (refractive index, extinction coefficient and transmission coefficient) is analyzed at 0.075 and 0.713 THz frequency points. The experimental results show that the density and refractive index of glass fiber composites decrease with the increase of porosity. When the frequency is 0.075 THz, the extinction coefficient decreases and the transmission coefficient increases with the increase of porosity based on Rayleigh scattering theory. At 0.713 THz, based on Mie scattering theory, the extinction coefficient increases and the transmission coefficient decreases with the increase of porosity. In addition, the complex and changeable pore morphology results in a non-unique correspondence between porosity and terahertz characteristic parameters. When the different samples have the same porosity, the terahertz characteristic parameters are not the same.

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• Simulation on the saturation properties of HgCdTe mid-wave infrared detectors

  Li Xiangyang, Sang Maosheng, Xu Guoqing, Qiao Hui, Chu Kaihui, Yang Xiaoyang, Yang Pengling, Wang Dahui

  Abstract: (79) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The photovoltaic mid-wave infrared HgCdTe detector, which is operated at room temperature, is simulated to explore laser irradiation saturation characteristics. The results reveal that the heating effect on the HgCdTe material and the lowering of the zero-bias impedance due to irradiation, are significant factors affecting the quantum efficiency of the detector. The model of HgCdTe pn junction is established, and a one-dimensional numerical simulation method is adopted to compute the quantum efficiency and zero-bias impedance of device. The device is irradiated under steady-state. Moreover, the temperature field distribution is coupled in the simulation, the thickness of substrate affects the temperature of the chip, which significantly affects the saturation threshold of the device. Furthermore, the calculations show that the zero-bias impedance of device decreases, when the light intensity is raised. The result is compared to the measured performance of device. Finally, the computational analysis serves as a foundation for the development of mid-wave IR HgCdTe detectors with high saturation irradiance thresholds.

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Volume 41,2022 Issue 5

• LOW-TEMPERATURE RAMAN SCATTERING SPECTRA AND ELECTRICAL PROPERTIES OF Cd_1-xZn_xTe(x=0.04) OF DIFFERENT SURFACE TREATMENTS

  PEI Hui-Yuan

  2001,20(3):184-188, DOI:

  Abstract: (1426) HTML (139) PDF (262.82 KKB)(48806)

  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。

• OPTICAL PROPERTIES OF PbTiO3 THIN FILMS PREPARED BY A MODIFIED SOL-GEL PROCESSING

  HU Zhi Gao WANG Gen Shui HUANG Zhi Ming CHU Jun Hao

  2002,21(3):175-179, DOI:

  Abstract: (7588) HTML (465) PDF (411.06 KKB)(19720)

  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。

Infrared Spectroscopy and Spectral Analysis

• DETECTING THE MELAMINE OF PURE MILK BY NEAR INFRARED SPECTRA

  XU Yun, WANG Yi-Ming, WU Jing-Zhu, ZHANG Xiao-Chao

  2010,29(1):53-56, DOI:

  Abstract: (10386) HTML (415) PDF (221.64 KKB)(13255)

  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.

• INFRARED OBJECT TRACKING BASED ON PARTICLE FILTERS

  CHENG Jian, ZHOU Yue, CAI Nian, YANG Jie

  2006,25(2):113-117, DOI:

  Abstract: (7182) HTML (402) PDF (271.63 KKB)(12871)

  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.

Image Processing and Software Simulation

• IMAGE SEGMENTATION BY SPECTRAL CLUSTERING ALGORITHM WITH SPATIAL COHERENCE CONSTRAINTS

  JIA Jian-Hua, JIAO Li-Cheng

  2010,29(1):69-74, DOI:

  Abstract: (11088) HTML (387) PDF (808.83 KKB)(10411)

  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.

• INFRARED TARGET EXTRACTION ALGORITHM BY USING PARTICLE SWARM OPTIMIZATION PARTICLE FILTER

  ZHOU Yue, MAO Xiao-Nan

  2010,29(1):63-68, DOI:

  Abstract: (11105) HTML (439) PDF (750.21 KKB)(9805)

  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.

• HYPERSPECTRAL REMOTE SENSING IMAGE CLASSIFICATION BASED ON SUPPORT VECTOR MACHINE

  TAN Kun, DU Pei-Jun

  2008,27(2):123-128, DOI:

  Abstract: (2812) HTML (936) PDF (735.00 KKB)(9495)

  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.

• 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: (11590) HTML (435) PDF (1.12 MKB)(9304)

  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.

• IMAGE RETRIEVAL BASED ON IMAGE ENTROPY AND SPATIAL DISTRIBUTION ENTROPY

  SUN Jun-Ding, DING Zhen-Guo, ZHOU Li-Hua

  2005,24(2):135-139, DOI:

  Abstract: (1255) HTML (99) PDF (380.01 KKB)(8674)

  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.

• RESEARCH ON ELECTRO-INDUCED BIREFRINGENCE IN CRYSTAL SILICON

  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: (7677) HTML (181) PDF (466.11 KKB)(7986)

  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.

Terahertz and Millimeter Wave Technology

• Design and experimental verification of band-pass frequency selective surface based on metamaterial effective medium theory

  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: (2397) HTML (131) PDF (1.09 MKB)(7680)

  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.

Image Processing and Software Simulation

• HYPERSPECTRAL ANOMALY DETECTION ALGORITHM BASED ON BACKGROUND RESIDUAL ERROR DATA

  LI Jie, ZHAO Chun-Hui, MEI Feng

  2010,29(2):150-151, DOI:

  Abstract: (2426) HTML (62) PDF (571.44 KKB)(7500)

  Abstract:

  In order to overcome the serious background interferences for small target detection of hyperspectral imagery, a nonlinear anomaly detection algorithm based on the background residual error data was proposed. After the background endmembers were extracted, spectral unmixing technique was applied to all mixed spectral pixels to separate target information from complicated background clutter.Then, the unmixing residual error data that included abundant target information was mapped into a high-dimensional feature space by a nonlinear mapping function. Nonlinear information between the spectral bands of hyperspectral imagery was exploited and the anomaly targets could be detected by using RX operator in the feature space. Thus, the ninlinear statistical characteristics between the hyperspectral bands were used effectively on the basis of suppressing the large probability background information. Numerical experiments were conducted on real AVIRIS data to validate the effectiveness of the proposed algorithm. The detection results were compared with those detected by the classical RX algorithm and KRS which did not suppress the backguound information. The results show that the proposed algorithm has better detection performance, lower false alarm probability and lower computational complexity than other detection algorithms.

Terahertz and Millimeter Wave Technology

• Passive millimeter wave focal plane array imaging technology

  WANG Nan-Nan, QIU Jing-Hui, ZHANG Peng-Yu, DENG Wei-Bo

  2011,30(5):419-424, DOI:

  Abstract: (3432) HTML (195) PDF (1.64 MKB)(7446)

  Abstract:

  Under the background of safety inspection, the key technologies of near-range passive millimeter wave focal plane array imaging are studied. The analysis of the system quasi-optics were carried out using fundamental Gaussian beam method combined with geometrical optics method. A multi-beam wide-angle scanning lens antenna was designed. A new dielectric rod antenna was devised, which is prone to be aligned in close arrays and provide good radiation to the lens. Miniaturized direct-detection radiometers were fabricated with high-sensitive in Ka-band . Experimental results of the 20-channel passive millimeter wave focal plane array imaging system are presented, which can be used to detect hidden objects on human bodies in near range indoors.

Infrared Materials and Devices

• Temperature dependent characteristics of HgCdTe variable-area photovoltaic detectors on Si substrates

  ZHANG Shan, HU Xiao-Ning

  2011,30(5):412-414, DOI:

  Abstract: (5056) HTML (160) PDF (704.75 KKB)(7280)

  Abstract:

  The variable-area HgCdTe/Si photovoltaic detector was investigated in this paper. By analyzing the relationship of dark current density (J) and the ratio of perimeter to area (p/A) under different reverse bias, it is indicated that the n-on-p type HgCdTe/Si photovoltaic detector has a significant surface leakage current under larger reverse bias. The minority carrier diffusion length at different temperature can be obtained by fitting the relationship between the product of zero-bias resistance and area (R0A) and p/A. It shows that the minority carrier diffusion length increases with the increase of temperature below 200 K, while the minority carrier diffusion length decreases with the increase of temperature above 200 K. The minority carrier lifetime of Hg-vacancy p-type HgCdTe on Si substrate was calculated from the minority diffusion length at different temperature. It was concluded that the lifetime of HgCdTe/Si minority carrier and its relationship with the temperature is the same as that of HgCdTe/CdZnTe material by comparing the minority carrier lifetime for these two kinds of materials.

• ANISOTROPIC GAUSSIAN FILTERING FOR INFRARED IMAGE

  WANG Huai-Ye, ZHANG Ke, LI Yan-Jun

  2005,24(2):109-113, DOI:

  Abstract: (1754) HTML (111) PDF (363.60 KKB)(7090)

  Abstract:

  为了在抑制噪声时尽可能保留图像边缘信息，提出一种自适应各向异性高斯滤波器设计方法．该方法由独立强度传播(IDS)模型决定滤波器的长轴尺度，由像素的邻域平滑度决定长短轴的比例，然后根据该处的灰度梯度方向自适应决定各向异性滤波器的长轴方向．仿真实验表明，提出的自适应各向异性滤波器具有很强的噪声抑制和边缘保持能力．

• INFLUENCE OF DEPOSITION POWER ON THE COMPOSITION, STRUCTURE AND PROPERTIES OF PZT THIN FILMS PREPARED BY RF SPUTTERING

  LI Xin-Xi 1, LAI Zhen-Quan 1, WANG Gen-Shui 2, SUN Jing-Lan 2 ZHAO Qiang 2, CHU Jun-Hao 2

  2004,23(4):313-316, DOI:

  Abstract: (1450) HTML (109) PDF (520.22 KKB)(7053)

  Abstract:

  用射频(RF)溅射法在镀LaNiO3(LNO)底电极的Si片上沉积PbZr0.52 Ti0.48 O3(PZT)铁电薄膜，沉积过程中基底温度为370℃，然后在大气环境中对沉积的PZT薄膜样品进行快速热退火处理(650℃，5min)．用电感耦合等离子体发射光谱(ICP-AES)测量其组分，X射线衍射(XRD)分析PZT薄膜的结晶结构和取向，扫描电子显微镜(SEM)分析薄膜的表面形貌和微结果，RT66A标准铁电综合测试系统分析Pt／PZT／LNO电容器的铁电与介电特性，结果表明，PZT薄膜的组分、结构和性能都与溅射沉积功率有关．

Terahertz and Millimeter Wave Technology

• Development and application of the millimeter wave SAR

  WANG Hui, ZHAO Feng-Jun, DENG Yun-Kai

  2015,34(4):452-459, DOI: 10.11972/j.issn.1001-9014.2015.04.013

  Abstract: (2995) HTML (165) PDF (3.92 MKB)(7014)

  Abstract:

  Synthetic aperture radar (SAR) is a microwave remote sensing radar with capability of all-day and all-weather imaging. Millimeter-wave SAR has become important for development of SAR with the advantage of small volume, light weight, and high resolution. The basic principle for high resolution imaging of millimeter-wave SAR is analyzed, and the advantage of millimeter-wave SAR is present. The state-of-art in the development of millimeter-wave SAR technologies and systems are illustrated with some typical millimeter-wave SAR systems. The application prospects, some issues, and future development trend of millimeter-wave SAR are also discussed.

Image Processing and Software Simulation

• INFRARED IMAGING MODEL FOR SCENE SIMULATION AND ITS VALIDATION

  LI Hong-Ning, BAI Ting-Zhu, CAO Feng-Mei, MA Shuai, XU Kai-Da, YANG Wei-Ping, FENG Jie

  2010,29(1):57-62, DOI:

  Abstract: (2819) HTML (136) PDF (472.80 KKB)(6961)

  Abstract:

  Based on the illumination model which is widely used in computer graphics and the radiance transfer law, a simplified thermal infrared imaging model is derived by: 1) adding the surface temperature distribution and the material parameters to the geometric model, 2) introducing the self emission and the detector property into the Illumination model. Using this model, the ray tracing method is applied to construct an infrared imaging system which can get the synthetic infrared images from any angle of view of the 3D scenes. Three typical 3D scenes are made to validate the infrared imaging model, and the infrared images are calculated to compare and contrast with the real infrared images obtained by a middle infrared band imaging camera. It shows that the thermal infrared imaging model is capable of producing infrared images which are very similar to those received by thermal infrared camera. Quantitative analysis shows that the absolute brightness does not match well, and the reasons are analyzed.

• STUDY ON HIGH RESOLUTION TIME INTERVAL MEASUREMENT MODULE IN PULSED LASER RANGING SYSTEM

  WU Gang, LI Chun-Lai, LIU Yin-Nian, DAI Ning, WANG Jian-Yu

  2007,26(3):213-216221, DOI:

  Abstract: (2088) HTML (213) PDF (268.18 KKB)(6878)

  Abstract:

  The precision of the pulsed laser ranging system was decided by the precision of the time interval measurement. Therefore, a high resolution time interval measurement module was developed. The module is based on the special time-to-digital conversion chip which adopts the delay line interpolation method. The maximum measuring time of the module is 200ms, and the maximum time resolution is 125ps, of which the corresponding distance resolution is 18.75mm. The module is especially suit for the large distance measurement. The hardware and the software of the module as well as the testing results are also presented.

• METHOD ON DESIGNING AND TRAINING OF ARTIFICIAL NEURAL NETWORK BASED ON GENETIC ALGORITHM

  WU Yan, WAN Wei

  2007,26(1):65-68, DOI:

  Abstract: (1227) HTML (98) PDF (183.75 KKB)(6695)

  Abstract:

  A method for designing and training artificial neural network based on genetic algorithm(NNDT) was presented.NNDT trains both architectures and weights of networks simultaneously.The problem that the one-to-one relationship between the topology and the encoding can not be kept was solved effectively.Heuristic method was used to constraint the probability of topology mutation and the trend of the choice of the kind of mutation.Also,the niching mechanism was used to protect the mutation of network topologies.The experiments results show the efficiency and rapidity of NNDT.