Volume 41,2022 Issue 3

Infrared Materials and Devices

• Recent progress on natural biomaterials boosting high-performance perovskite solar cells

  XIONG Shao-Bing, BAO Qin-Ye, CHU Jun-Hao

  2022,41(3):517-533, DOI: 10.11972/j.issn.1001-9014.2022.03.001

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  Abstract:

  Perovskite solar cells （PeSCs） have been considered as one of the most promising photovoltaic technologies due to their high efficiency， low-cost and facile fabrication process. The power conversion efficiency and stability of PeSCs highly depend on the quality of perovskite film and the interfaces in the device， which are the main sources of PeSCs nonradiative recombination losses. Natural biomaterials， with the advantages of earth-abundance， non-toxicity， and biocompatibility， have shown huge potential to improve both perovskite layer and interfaces in PeSCs. Herein， the latest progress using natural biomaterials to achieve high-performance PeSCs is reviewed. It’s discussed the roles of natural biomaterials on perovskite film in terms of morphology optimization， defect passivation and energetics modification. Meanwhile， the strategies using natural biomaterials to create a superior interface between the perovskite and charge transport layer， and to build stretchable， biocompatible， and biodegradable electrodes are present. Finally， an outlook on the further development of PeSCs with respect to natural biomaterials is provided.

• Research on p-on-n LWIR and VLWIR HgCdTe infrared focal plane detectors technology

  LI Li-Hua, XIONG Bo-Jun, YANG Chao-Wei, LI Xiong-Jun, WAN Zhi-Yuan, ZHAO Peng, LIU Xiang-Yun

  2022,41(3):534-539, DOI: 10.11972/j.issn.1001-9014.2022.03.002

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  Abstract:

  The p-on-n structure doped with As implantation has the advantages of low dark current，high R₀A product， and long minority carrier lifetime，which is an important trend in the development of long-wavelength and very long-wavelength HgCdTe infrared focal plane detectors. P-on-n LWIR and VLWIR HgCdTe infrared focal plane detectors with cut-off wavelength of 9.5 μm and 10.1μm at 77 K and 14.97 μm at 71 K fabricated by Kunming Institute of Physics are introduced.Test and analyze performance parameters such as the responsivity， NETD， dark current and R₀A of the detectors. The test results show that the operability of the detectors is between 99.78% and 99.9%，and the NETD of the detectors is less than 21 mK. The effective fabrication of p-on-n LWIR and VLWIR HgCdTe infrared focal plane detectors is realized.

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• Tunable dual-wavelength semiconductor laser based on indium-rich cluster quantum structure

  LI Xue, TAI Han-Xu, WANG Yu-Hong, ZHENG Ming, ZHANG Jian-Wei, ZHANG Xing, NING Yong-Qiang, WU Jian, WANG Li-Jun

  2022,41(3):540-544, DOI: 10.11972/j.issn.1001-9014.2022.03.003

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  Abstract:

  We design and fabricate a double-wavelength tunable laser with a single grating structure using a single-gain chip. The gain chip adopts an indium-rich cluster quantum constraint structure， which can generate ultra-wide flat-top gain. The flat-top gain is the basis for producing a dual-wavelength laser with the same intensity. A grating is inserted into the exterior of the gain chip so that its resonator is composed of internal and external cavities. The internal cavity consists of two natural cleavage planes of the gain chip for oscillating the output laser at a fixed wavelength （974 nm）. The tunable external cavity consists of a natural cleavage plane and a grating for the output laser at a tunable wavelength （969.1~977.9 nm）. The laser structures of the single-gain chip and single grating can produce synchronous dual-wavelength output， which avoids a complicated optical path design. The frequency difference between the two wavelengths is in the terahertz band. Thus， the laser can be used as a dual-wavelength laser source to generate terahertz radiation.

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• Dual-color mid- mid-wavelength infrared InAs / InAsSb superlattice focal plane arrays

  HE Ying-Jie, PENG Zhen-Yu, CAO Xian-Cun, ZHU Xu-Bo, LI Mo, TAO Fei, DING Jia-Xing, YAO Guan-Sheng, ZHANG Li-Xue, WANG Wei, LYU Yan-Qiu

  2022,41(3):545-550, DOI: 10.11972/j.issn.1001-9014.2022.03.004

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  Abstract:

  Superlattice materials have become the preferred materials for the third-generation infrared focal plane detectors. The dual-band infrared detector can suppress the complex background and improve the detection effect by comparing the spectral information difference in the two bands， which is particularly important in demand. In this paper， it reports research results of 320 × 256 dual-color mid-mid-wavelength infrared InAs /InAsSb superlattice focal plane arrays. The detector structure is NBN epitaxial multilayer and the signal is read out by sequential mode. The pixel center distance from the detector is 30 μm. At 77 K measurement， the SMW detector has a peak detectivity of 7.2×10¹¹ cm·Hz^1/2W^-1 and dead pixels rate of 0.49%. The MW detector has a peak detectivity of 6.7×10¹¹ cm·Hz^1/2W^-1and dead pixels rate of 0.87%. Infrared images of both wavebands have been taken well-infrared imaging test by adjusting devices voltage bias．

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• Room-temperature THz detection via EIW effect based on graphite nanosheet

  YAN Jiang-Wei, ZHANG Xiao-Dong, ZHOU Wei, MA Wan-Li, HU Tao, YAO Niang-Juan, JIANG Lin, HUANG Zhi-Ming

  2022,41(3):551-556, DOI: 10.11972/j.issn.1001-9014.2022.03.005

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  Abstract:

  We demonstrate a room-temperature sub-terahertz photoconductive detector based on graphite nanosheet （GN） using electromagnetic induced well （EIW） effect produced in the metal-GN-metal structure. The detector achieves high performance of room-temperature THz detection. It shows a responsivity of over 20 kV/W at 0.035 THz and 11 kV/W at 0.1673 THz， as well as NEP of about 1.25 pW/Hz^1/2 at 0.035 THz and 2.27 pW/Hz^1/2 at 0.1673 THz， respectively. The results open up a new idea for graphene-based THz detection.

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Terahertz and Millimeter Wave Technology

• Design of a quasi-optical mode converter for a 170 GHz gyrotron

  XU Shou-Xi, YANG Jie, WANG Hu, GENG Zhi-Hui, ZHANG Rui

  2022,41(3):557-562, DOI: 10.11972/j.issn.1001-9014.2022.03.006

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  Abstract:

  A high efficiency Denisov-type quasi-optical mode converter for a 170 GHzmode gyrotron is presented. The mode converter comprises a dimpled-wall launcher and a mirror system. Based on the coupled mode theory， the advanced launcher having two stages of perturbations is investigated. A mirror system of the converter is optimized and designed by using the vector diffraction theory. Simulation results show that the good Gaussian mode is converted from the circular waveguide mode and the mode conversion efficiency of a quasi-optical mode converter is 93.7%.

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• High birefringence hollow-core anti-resonant terahertz photonic crystal fiber with ultra-low loss

  HUI Zhan-Qiang, YANG Xue, HAN Dong-Dong, LI Tian-Tian, ZHAO Feng, YANG Yi, CHEN Su-Guo

  2022,41(3):563-572, DOI: 10.11972/j.issn.1001-9014.2022.03.007

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  Abstract:

  An ultra-low loss and high birefringence hollow core anti-resonant terahertz photonic crystal fiber based on cyclic olefin copolymer （COC） is proposed. The cladding of the fiber consists of two groups （six in total） nodeless embedded sleeves. The guided wave characteristics are analyzed by using the finite difference time domain method combined with the perfectly matched layer boundary conditions. The simulation results show that the total transmission loss is less than 0.1 dB/m， birefringence is more than 2.12×10^-5 within the range of 0.8-1.35 THz， dispersion in ±0.027 ps/THz/cm. At 1.12 THz， the minimum total transmission loss is only 0.543×10^-2 dB/m， birefringence value 2.06×10^-4. The bending performance of the fiber is analyzed. It is shown that in y direction， when the bending radius is more than 19 cm， the bending loss is less than 0.1 dB/m， and the bending performance is good.

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• A wideband injection-locked frequency tripler

  WAN Cao, XUE Quan

  2022,41(3):573-580, DOI: 10.11972/j.issn.1001-9014.2022.03.008

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  Abstract:

  The article proposes a wideband injection-locked frequency tripler （ILFT）. Based on the conventional injection method， the tripler used a push-push differential pair to double the frequency of the input signal and coupled the generated second harmonic to the source common mode node of the injectors through a transformer， which enhanced the second harmonic at the source common mode node of the injectors. Since the injection current is generated by mixing the injected signal with the second harmonic at the source common mode node， the injection current is also enhanced， thereby increasing the locking range. In addition， the tripler adopted a fourth-order resonator， as a result， the phase of the resonant impedance is flattened at the zero-crossing point， then the locking range is further increased. The tripler is implemented in a standard CMOS 65-nm process with a chip area of 720×670 μm²， and the power consumption is 15.2 mW under a 1.2-V power supply. With 0 dBm power injection， the locking range is 19.2-27.6 GHz， the corresponding fundamental suppression ratio is greater than 25 dB， and the second harmonic counterpart is beyond 35 dB. The proposed ILFT is capable of the requirements of the oscillation source of the 5G transceiver.

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Infrared Spectroscopy and Spectral Analysis

• A THz-TDS based metamaterial sensor for the sensitive distinguishment of food additives

  MA Jia-Lu, TANG Jing-Chao, WANG Kai-Cheng, GUO Liang-Hao, WANG Shao-Meng, GONG Yu-Bin

  2022,41(3):581-588, DOI: 10.11972/j.issn.1001-9014.2022.03.009

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  Abstract:

  A sensitive terahertz （THz） metamaterial sensor for the distinguishment of common additives in the food industry is proposed. The metamaterial sensor consists of an array of split ring resonator （SRR） with double tip ends. By checking resonate frequency shift of the sensor， the concentration and the type of the solution sample can be distinguished. The metamaterial sensor is fabricated on a quartz substrate， which is transparent for THz wave. The solutions with the concentration of 0.2， 0.4， 1.5， 2， 3 and 4 mg/ml have been measured by using a terahertz time domain spectroscopy （THz-TDS）. The results illustrate that the proposed metamaterial sensor can detect the concentration of the solution sample， as low as 0.2 mg/ml. Meanwhile， different solutions with same concentration can also be clearly distinguished. Our study provides new insights for the application of terahertz metamaterial sensor based on SRR structure in the field of food safety.

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• Terahertz detection of thin defects thickness based on Hilbert transform and power spectrum estimation

  WANG Jie, TAN Bing-Chong, TAO Xing-Zhu, XU Cheng-Cheng, CHANG Tian-Ying, CUI Hong-Liang, ZHANG Jin

  2022,41(3):589-596, DOI: 10.11972/j.issn.1001-9014.2022.03.010

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  A spectral analysis algorithm based on the combination of Hilbert transform （HT） and power spectrum estimation has been proposed， and the terahertz reflection time domain waveform was processed. At the same time， the algorithm was applied to terahertz time domain spectroscopy imaging， defect thickness was correlated with image gray level， and the thickness， position and shape of defects in glass fiber laminate can be detected by imaging simultaneously. The experimental results show that when the multi-signal classification （MUSIC） spectrum estimation and auto regressive （AR） spectrum estimation are combined with Hilbert transform， the reflected pulses between upper and lower surfaces of defect with thickness of 0.08 mm can be successfully distinguished， the time resolution of reflected pulses is higher than 0.5 ps， and the detection error of defect thickness is no more than 0.03 mm.

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• Nonlinearity correction of FY-3E HIRAS-II in pre-launch thermal vacuum calibration tests

  YANG Tian-Hang, GU Ming-Jian, SHAO Chun-Yuan, WU Chun-Qiang, QI Cheng-Li, HU Xiu-Qing

  2022,41(3):597-607, DOI: 10.11972/j.issn.1001-9014.2022.03.011

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  The High-spectral Infrared Atmospheric Sounder II （HIRAS-II） is a Fourier transform spectrometer onboard the world’s first civil early-morning-orbiting FengYun 3E （FY-3E） meteorological satellite， the FY-3E/HIRAS-II focus on a number of upgrades such as the sensitivity of the detector， the accuracy of spectral calibration and radiometric calibration， with the designed and manufactured processing based on the first Chinese hyperspectral infrared （IR） sounder FY-3D/HIRAS-I. We conducted a comprehensive pre-launch thermal vacuum （TVAC） calibration tests for HIRAS-II， including the nonlinearity （NL） correction which consists an essential part of radiometric calibration， the NL correction has considerable effects on radiometric accuracy. According to the HIRAS-II nonlinear behavior of the detectors for long-wave （LW） and mid-wave1 （MW1） infrared spectral bands， the NL correction of raw data in the spectral domain is a scaling of the observed spectrum， the NL correction coefficients are derived by the methods of minimizing the spread of the responsivity of reconstructed spectrum in each wavenumber with varying temperature， or minimizing the spread of the bias of brightness temperature among calibration targets with varying temperature. The bias of spectral brightness temperature is assessed by comparing the NL correction and the non-NL correction radiometric calibration data， the results show that， the radiometric accuracy has been significantly improved via NL correction.

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Remote Sensing Technology and Application

• Study on the improvement of scan mirror thermal radiation correction on the calibration accuracy of FY-4A AGRI

  LI Xiu-Ju, WANG Bao-Yong, WU Ya-Peng, HAN Chang-Pei, CAO Qi, ZHOU Shu-Tian, WANG Wei-Cheng, LI Pan-Pan

  2022,41(3):608-617, DOI: 10.11972/j.issn.1001-9014.2022.03.012

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  Abstract:

  The Advanced Geostationary Radiation Imager （AGRI） is one of the main payloads of Fengyun-4A （FY-4A）. In order to satisfy requirements of high-accuracy quantitative application of AGRI long-wave infrared （LWIR） remote sensing data， a function model of scan mirror thermal radiation changing with mechanical rotation angle is constructed， and a correction algorithm for remote sensing data of on-board blackbody and earth scene observation is presented. Based on the on-orbit data of FY-4A AGRI， the dependence of the model parameters on the scan mirror temperature is analyzed， and the improvement effect of the correction algorithm on the calibration accuracy of LWIR is studied and evaluated. After thermal radiation correction of scan mirror in the stationary period of mirror temperature field， the calibration deviation of B11（8.0~9.0 μm）， B12（10.3~11.3 μm）， B13（11.5~12.5 μm） can be improved significantly by -2.81 K~+1.06 K， -0.60 K~+0.19 K， -0.68 K~+0.24 K respectively. The result of inter-calibration validation with IASI shows that the improved on-orbit calibration brightness temperature bias is better than 0.5 K@290 K.

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• The research on lightweight SAR ship detection method based on regression model and attention

  LI Li-Yuan, LI Xiao-Yan, HU Zhuo-Yue, SU Xiao-Feng, CHEN Fan-Sheng

  2022,41(3):618-625, DOI: 10.11972/j.issn.1001-9014.2022.03.013

  Abstract: (1) HTML (0) PDF (1.32 MKB)(0)

  Abstract:

  Synthetic aperture radar （SAR） has the advantages of all-sky and all-weather earth observation without cloud interference. Ship detection based on SAR images has been widely used in civil and military fields， including maritime search and rescue， port reconnaissance， territorial sea defense. However， different from large ships， the misdetection rate of small ships with fewer pixels and lower contrast is high. And it is difficult to balance speed and accuracy during on-orbit ship detection. To solve the above problems， an improved lightweight ships detection method （ImShips） based on YOLOv5s is proposed. Firstly， the standard convolution with small receptive field is adopted at the bottom of the baseline to obtain spatial information about small ships. And the dilated convolution with enlarged receptive field is added at the top of the baseline to preserve more semantic features， which is conducive to extract large targets feature. Then， a lightweight channel attention mechanism is applied to the backbone and neck of YOLOv5. And the weight is allocated to filter more important texture information. Finally， the depth-wise separable convolution is adopted to replace the standard convolution during down-sampling to reduce the number of parameters and improve the inference speed. Compared with YOLOv5s model， the experimental results show that ImShips achieve an increase in AP， while the FLOPs are reduced by 45.61%， and the speed is increased by 8.31% in SSDD and ISSID datasets. The speed and accuracy of ImShips model are improved effectively on sea surface object detection. The proposed method has great application potential for on-orbit ship detection.

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Infrared Photoelectric Technology and Application

• Design of a novel Y-junction electro-optic modulator based on thin film lithium niobite

  GUO Hong-Jie, LIU Hai-Feng, WANG Zhen-Nuo, TAN Man-Qing, LI Zhi-Yong, Lei Ming, GUO Wen-Tao

  2022,41(3):626-630, DOI: 10.11972/j.issn.1001-9014.2022.03.014

  Abstract: (1) HTML (1) PDF (879.42 KKB)(0)

  Abstract:

  In recent years， the high-performance electro-optic modulator based on the thin-film lithium niobate （TFLN） platform has been receiving considerable attention due to the featuring small footprint and low energy loss. In this paper， a novel Y-junction electro-optic modulator with a vertical electrode structure was designed based on TFLN. The relationship between the low half-wave voltage and the buffer layer thickness for the novel modulator was investigated. Meanwhile， the design parameters of Y-junction were optimized， and found that the half-wave voltage is less than 1.5 V and the insertion loss is less than 5 dB. Finally， the Y-junction electro-optic modulator was fabricated. This study not only provides insights on the design and realization of compact footprint photonic waveguides in the TFLN platform but also， experimental evidence for the fabrication of electro-optic modulators with high-performance and multifunction.

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• Analysis and verification of the positioning accuracy of a flat-panel detector used for precision pointing in space optical communication

  WANG Xu, TU Cheng-Xiang, ZHANG Liang, WANG Jian-Yu

  2022,41(3):631-638, DOI: 10.11972/j.issn.1001-9014.2022.03.015

  Abstract: (0) HTML (0) PDF (602.00 KKB)(0)

  Abstract:

  To realize a high-precision link in space optical communication， we analyzed key factors that affect the accuracy of flat-panel detectors in terms of target positioning. The error of the centroid algorithm was analyzed from the mechanism and the necessity of satisfying the spatial lossless sampling condition was verified by using a simulation. The defined NU value served as an indicator in quantifying the nonuniformity of the detector. As the NU value increased linearly， the positioning error of the centroid continued to increase， whereas the speed reduced. When the NU value was 0.005， the maximum positioning error was 0.043 pixels. Considering that the light intensity of the target incident on the optical system varies constantly， the smaller the NU value， the closer the centroid is to the true position of the light spot. Furthermore， the pixel response of a typical complementary metal oxide semiconductor （CMOS） detector was experimentally tested under different illumination intensities. Based on the response curve， a mathematical model for the nonuniformity of the pixel response was established. It can be determined that the NU value fluctuates from 0.0045 to 0.0048 within the linear response range. The experimental results of the spot centroid positioning accuracy verify that the absolute positioning error is less than 0.05 pixels， which satisfies the requirements of high-precision links. Therefore， the effectiveness of the theory and simulation presented in this study can be validated.

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Image Processing and Software Simulation

• Fast moving target detection algorithm based on LBP texture feature in complex background

  QIU Li-Ya, CHEN Wei-Lin, LI Fan-Ming, LIU Shi-Jian, LI Zheng, TAN Chang

  2022,41(3):639-651, DOI: 10.11972/j.issn.1001-9014.2022.03.016

  Abstract: (0) HTML (0) PDF (1.96 MKB)(0)

  Abstract:

  In the visible and infrared scenes with complex background， such as rain and snow weather， leaf swaying， shimmering water， etc.， fast and accurate extraction of a complete target has always been the primary problem in moving target detection. In order to be real time and aiming at the problems of existing video foreground extraction algorithms， such as dependence on prior information， low recall rate， lack of texture and large noise， a background modeling method based on histogram statistics and improved LBP （Local Binary Pattern） texture features is proposed. Firstly， the mode of each pixel histogram is used as the reference background without prior knowledge， which saves a lot of storage space. Then， an improved S_MBLBP texture histogram is proposed to model the background with the reference background by using neighborhood compensation strategy， which eliminates the most dynamic background and illumination changes， and realizes the accurate extraction of the target. Experimental results show that the proposed algorithm can quickly extract foreground targets in a variety of complex infrared and visible scenes， and can improve the accuracy and recall rate at the same time.

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• Anisotropic tunable multi-order strong coupling in black phosphorous nanodisk-sheet plasmonic system

  HAN Li, XING Huai-Zhong

  2022,41(3):652-658, DOI: 10.11972/j.issn.1001-9014.2022.03.017

  Abstract: (0) HTML (0) PDF (1.03 MKB)(0)

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  Black phosphorus supports anisotropic surface plasmons， which can be used to design principle devices with more functions. The hybridization behavior of different plasmon modes in the sheet-disk-sheet system based on black phosphorus in the mid-infrared to far-infrared waveband is numerically simulated by the finite-difference time-domain method. By dynamically adjusting the carrier concentration in the black phosphorus， the generation and control of the strong coupling phenomenon in the two lattice directions can be realized. Analyzing and calculating the coupling between different modes， the Rabi splitting energy in the absorption spectrum can be as high as 42.9 meV. In addition， the influence of the polarization angle on the strong anisotropic coupling is also calculated， which can achieve up to 6 absorption bands. The proposed model provides a basis for the construction of compact anisotropic plasmonic devices based on two-dimensional materials that will work in the mid-to-far infrared bands in the future.

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Volume 41,2022 Issue 3

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: (22) HTML (0) PDF (1.64 MKB)(0)

  Abstract:

  Uncooled infrared imaging technology has a very broad application prospect. However， there are some urgent problems to be solved， such as nonuniformity 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 nonuniformity 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 65nm 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 2W， 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: (28) HTML (0) PDF (901.64 KKB)(0)

  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.

红外材料与器件

• 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

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

  Abstract: (39) HTML (0) PDF (1.05 MKB)(2)

  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^-9A/cm² at -10mV at 150K. The cutoff wavelength and peak wavelength were 2.12μm and 1.97μm. The peak detectivity， peak responsivity and quantum efficiency was 1.01×10¹²cm·Hz^1/2/W， 1.29A/W and 82% respectively. These results suggest that the planar-type InGaAs can reach high performance.

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

  Shen Chuan, Yang Liao, Liu Yangrong, Bu Shundong, Wang Gao, Chen Lu, He Li

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

  Abstract: (41) HTML (0) PDF (1.07 MKB)(1)

  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.

遥感技术与应用

• 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

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

  Abstract: (28) HTML (0) PDF (1.62 MKB)(0)

  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 can not 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.

太赫兹与毫米波技术

• Design of a 1030 GHz mixer and a 750-1100 GHz tripler based on thin-film technology

  MENG Jin, ZHANG De-hai, NIU Bin, ZHU Hao-tian, LIU Si-yu, FAN Dao-yu, CHEN Shen-tang, ZHOU Ming

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

  Abstract: (30) HTML (0) PDF (1.30 MKB)(0)

  Abstract:

  Based on the GaAs process of Nanjing electronic devices institute， a 750-1100 GHz tripler and a low loss subharmonic mixer with center frequency of 1030 GHz have been independently 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 3μm thick monolithic circuit is supported in the cavity structure through beam lead. The measured result shows that the output power of the broadband frequency multiplier is -23 ~ -11 dBm in the frequency range of 790~1100 GHz. Using the above frequency multiplier source as the RF signal to test the subharmonic mixer， the conversion loss is better than 17.5 dB in the frequency range of 1020 ~ 1044 GHz， and the minimum conversion loss measured at 1030 GHz is 14.5 dB.

红外及光电技术与应用

• 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

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

  Abstract: (68) HTML (0) PDF (855.03 KKB)(0)

  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.

太赫兹与毫米波技术

• 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

  DOI:

  Abstract: (49) HTML (0) PDF (1.46 MKB)(0)

  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 tripler， 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 for a 1 THz solid-state external super outlier mixer.

图像处理及软件仿真

• 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: (72) HTML (0) PDF (1.48 MKB)(0)

  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.

红外材料与器件

• 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: (85) HTML (0) PDF (1.03 MKB)(0)

  Abstract:

  High-power semiconductor laser with nearly diffraction limited narrowband emission was designed and fabricated. The monolithic master oscillator （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 （3dB）， 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

• An Ultra Efficient Streaming-based FPGA Accelerator for Infrared Target Detection

  Chen Shao-Yi, Tang Xin-Yi, Wang Jian, Li Zheng

  DOI:

  Abstract: (55) HTML (0) PDF (1.70 MKB)(1)

  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， and the algorithm is accelerated and deployed using Xilinx’s Ultrascale+MPSoC ZU3EG FPGA. The accelerator runs at a 350MHz frequency clock with throughput of 551FPS and power of only 8.4W. 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 power consumption

红外材料与器件

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

  Li XUE, Zhang JI-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: (87) HTML (0) PDF (892.08 KKB)(1)

  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 1.5W 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 than1.5W 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.

• Milimeterwave Schottky Diode Characterization and On-wafer Measurement

  ZHANG Ao, GAO Jianjun

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

  Abstract: (43) HTML (0) PDF (1.16 MKB)(0)

  Abstract:

  In this paper， the one-port he 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 used to extract the small signal model parameters. The experimental results show that the S-parameters agree well under on and off bias condition.

• 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

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

  Abstract: (156) HTML (0) PDF (1.45 MKB)(0)

  Abstract:

  Very long wave 640×512 FPAs with 25μm pixel pitch and cutoff wavelength of 13.23μm， 14.79μm respectively at 77K were prepared by 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（77K）=13.23μm is 55%， the average NETD is 21.5mk， with an operability of 99.81%； The quantum efficiency of the VLWIR 640×512 FPAs with λ_c（77K）=14.79μm is 45%， the average NETD is 34.6mK， with an operability of 99.28%. The R₀A figures of merit at liquid nitrogen temperature are 19.8Ω·cm² and 1.56Ω·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.

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

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

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

  Abstract: (22) HTML (0) PDF (1.54 MKB)(0)

  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 as3×10^-6 A/cm²， the dark current density of the detectors were 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.

40周年特邀

• 基于偏振调节的太赫兹量子级联激光器双光梳研究

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

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

  Abstract: (8) HTML (0) PDF (1.04 MKB)(0)

  Abstract:

  太赫兹量子级联激光器（THz QCL）双光梳在光谱检测、测距、成像等领域具有重要应用。双光梳信号严重依赖THz耦合光功率。利用THz QCL激射光为线偏振光的特性，在双光梳光路上插入线偏振片，通过旋转偏振片以达到对THz光强进行调节的作用。系统研究了THz QCL双光梳谱和功率与偏振角度的依赖关系，为实现高稳定THz双光梳光源与应用奠定基础。

太赫兹与毫米波技术

• Study on longitudinal resolution enhancement of terahertz imaging based on empirical wavelet coefficient mode decomposition

  LI Zhi-Long, ZUO Jian, ZHAO Yuan-Meng, HAN Zhong-De, XU Zhi-Hao, ZHAO Yun-Zhang, YANG Chao, HU Wei-Dong, ZHANG Cun-Lin

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

  Abstract: (31) HTML (0) PDF (2.40 MKB)(48)

  Abstract:

  In order to improve the longitudinal resolution of terahertz imaging detection, a novel longitudinal resolution enhancement method based on empirical mode decomposition of continuous wavelet was proposed. Firstly, the frequency domain signals of the sample are processed by continuous wavelet transform to obtain the corresponding continuous wavelet transforms coefficients. Then, the obtained continuous wavelet coefficients are decomposed by empirical mode decomposition, which is adaptive decomposed into a series of intrinsic mode functions and a residual signal. And the first-order intrinsic mode functions are extracted as the imaging parameter for 3D reconstruction to obtain the final 3D intrinsic mode function image, so as improving the longitudinal resolution of terahertz detection image. In order to verify the effectiveness of the method, the 150 GHz~220 GHz high frequency terahertz frequency modulated radar imaging system was used to detect two kinds of sandwich structure composite material with internal adhesive debonding defects, and the proposed method was used to process them. The detection results images of the longitudinal resolution effectively enhanced and the sharpness effectively improved was obtained, which provides a new idea of future terahertz computer tomography imaging and terahertz non-destructive testing research.

红外光谱与光谱分析

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

  SHEN Shuai, HE Jian-Jun

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

  Abstract: (74) HTML (0) PDF (1.98 MKB)(135)

  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.

红外及光电技术与应用

• 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

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

  Abstract: (57) HTML (0) PDF (1.77 MKB)(280)

  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 0.15mJ (0.015W), 0.4mJ (0.04W) and 4mJ (0.4W), 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) arrays with a detection efficiency of 60% (@1064nm) is used, and background noise is suppressed by spatial filtering, temporal filtering and spectral filtering. Using 0.4mJ (0.04W) energy to perform laser ranging on the synchronous satellite in the daytime. Using 0.15mJ (0.015W) 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.

• 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: (101) HTML (0) PDF (1.05 MKB)(118)

  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.

太赫兹与毫米波技术

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

  DU Hai-Wei, LONG Jiang

  DOI:

  Abstract: (145) HTML (0) PDF (519.74 KKB)(125)

  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

  DOI:

  Abstract: (77) HTML (0) PDF (1.29 MKB)(96)

  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.

• 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

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

  Abstract: (211) HTML (0) PDF (1.82 MKB)(174)

  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.

红外光谱与光谱分析

• 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

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

  Abstract: (69) HTML (0) PDF (801.13 KKB)(235)

  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.

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: (639) HTML (0) PDF (0.00 ByteKB)(451)

  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.

40周年特邀

• Influence of inductance of photo-conductive terahertz source circuit on its radiation characteristics

  Shang Ting, Jin Zhi, Li Chunhui, Shi Wei

  DOI:

  Abstract: (27) HTML (0) PDF (0.00 ByteKB)(4)

  Abstract:

  Photo-conductive terahertz source (PCA) has been widely used in terahertz time domain spectral system (THz-TDS). In the THZ-TDS system, the biased PCA is triggered by femtosecond laser to radiate terahertz waves to free space due to the accelerated motion of photogenerated carriers under the bias electric field, and pulse current is formed in the PCA bias loop. Generally, the circuit that loads bias voltage to PCA has different circuit designs, so there is inevitably a certain inductance in the base circuit of PCA mounting. The electromagnetic inertia caused by this will significantly affect the pulse width of the current in the circuit, and the pulse width of the current pulse will be widened with the increase of the circuit inductance. Therefore, whether the inductance of The PCA circuit will affect the characteristic of THz wave radiated from PCA to free space is a problem faced by the design of the circuit based on PCA. In this paper, inductance elements with different inductance values are added to the PCA circuit, and the time domain waveform and spectrum of THz wave radiated by PCA are tested experimentally. The results show that the value of the inductance in the PCA circuit has no obvious effect on the THz wave radiated by PCA, thus providing experimental basis for the design of THz PCA substrate circuit applied in different occasions.

• 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

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

  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" test 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 1.565μm 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-.

  • 1
• The photon detection mode of photomultiplier tubes considering the pulse height distribution

  XIANG Yu-Yan, Ma Yue, Li Song

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

  Abstract:

  Photomultiplier tubes (PMT) have unique advantages in photon-counting radar 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 be stacking 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 setting of photon event identification threshold on the photon event detection probability, a new PMT photon detection theoretical model was proposed and simplified according to the actual application scenarios. The applicability of the simplified model was verified by Monte Carlo simulation. The correlation characteristics of the new model in photon counting distance measurement are analyzed. A photon counting radar system is built, compared with GM-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 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 radar.

  • 1
• A new positioning research for the footprints of GaoFen-7 spaceborne laser altimeter in mountainous region based on waveform matching method

  Wu Yu, Wang Heng, Han Qijin, Long Xiaoxiang, Ma Yue, Li Qingpeng, Zhao Pufan, Li Song

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

  Abstract:

  The SLA (spaceborne laser altimeter) borne on Gaofen-7 satellite is the first SLA with full-waveform recording for Earth observation. The horizontal and vertical accuracy of laser footprints are the most important technical indicators for a SLA. This paper proposes a method to improve the geolocation accuracy for laser footprints based on waveform simulating and matching. Using airborne lidar point cloud data as in-situ measurements, the laser pointing and ranging information are calculated and further calibrated by matching the simulated waveform with the Gaofen-7 captured waveform of a single footprint and combined treatment of successive footprints correlation coefficient within a laser track. Mountainous study areas (Utah states in USA) were selected. After using the proposed method, the residual of laser footprint elevations in Utah and Wyoming states was improved from 2.54m to 0.27±0.61m with the mean surface slope of approximately 20°, respectively. The results indicate that the proposed method can improve the data accuracy of Gaofen-7 SLA in mountainous areas with the help of in-situ DEM (digital elevation model) data.

  • 1
• Development of imaging model of infrared camera with focal plane detector and its MTF measuring method.

  Kong Jian, Fu Yu-Tian, Zhao Yue-Jin

  Abstract: (12) HTML (0) PDF (0.00 ByteKB) (0)

  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.

  • 1
• 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: (16) 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.

  • 1
• Study on Molecular Beam Epitaxy of High indium InGaAs Films

  YANG Ying<sub>, 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

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

  Abstract:

  The cutoff wavelengths of short-wave infrared photodetectors with high indium composition InGaAs films are beyond 1.7 μm, attracting much attention owing to their important applications. 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 dimers of In0.74Ga0.26As materials were investigated and adjusted to optimize the peak intensity of photoluminescence 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 In0.74Ga0.26As materials grown using As2 dimers show better material quality than those using As4 dimers. For the material grown at 570 ℃, As2 dimers and V/III ratio of 18, relatively strong photoluminescence 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 13400 cm²/Vs and 45160 cm²/Vs, respectively.

  • 1
• Optimum designs of micro-resonator photonic crystal waveguides with gradually?varied formations

  WU Li-Heng, Wang Ming-Hong

  Abstract: (43) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  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 resonator increases, single pass-band peak wavelength of every waveguide output shifts towards the longer wavelength. Transmission patterns of structural single pass-band 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.

  • 1
• Design of 220GHz power amplifier based on 90nm InP HEMT process

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

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

  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.

  • 1
• Design of high-frequency circuit for W-band CW sheet beam extended-interaction klystron

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

  Abstract: (37) HTML (0) PDF (0.00 ByteKB) (0)

  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.

  • 1
• 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, YANG Xin, GAO Song-Xin, TANG Chun

  Abstract: (38) HTML (0) PDF (0.00 ByteKB) (0)

  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.

  • 1
• 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

  Abstract: (46) HTML (0) PDF (0.00 ByteKB) (0)

  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.

  • 1
• Quantum well modulated optical pumped Vertical External Cavity Surface-Emitting Laserfor 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

  Abstract: (38) HTML (0) PDF (0.00 ByteKB) (0)

  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 highly sensitive detector. With the increasing of the pump power, stable dual-wavelength emission was achieved, the peak positions of emission wavelength are 966nm and 968nm respectively. The output power of the stable dual-wavelength emission can reach 560mW, and the far fields show Gaussian cross-sections in orthogonal dimensions, and the divergence angles of 6.68° and 6.87° are obtained.

  • 1

Volume 41,2022 Issue 3

• 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: (1381) HTML (139) PDF (262.82 KKB)(48344)

  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: (7530) HTML (465) PDF (411.06 KKB)(19498)

  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: (10324) HTML (415) PDF (221.64 KKB)(12961)

  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: (7150) HTML (402) PDF (271.63 KKB)(12587)

  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: (10999) HTML (387) PDF (808.83 KKB)(10151)

  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: (11049) HTML (439) PDF (750.21 KKB)(9560)

  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: (2759) HTML (936) PDF (735.00 KKB)(9115)

  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: (11507) HTML (435) PDF (1.12 MKB)(9064)

  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: (1196) HTML (99) PDF (380.01 KKB)(8192)

  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: (7645) HTML (181) PDF (466.11 KKB)(7759)

  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: (2351) HTML (131) PDF (1.09 MKB)(7379)

  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: (2401) HTML (62) PDF (571.44 KKB)(7276)

  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: (3368) HTML (195) PDF (1.64 MKB)(7148)

  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: (5027) HTML (160) PDF (704.75 KKB)(7038)

  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.

• 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: (1422) HTML (109) PDF (520.22 KKB)(6809)

  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．

• ANISOTROPIC GAUSSIAN FILTERING FOR INFRARED IMAGE

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

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

  Abstract: (1714) HTML (111) PDF (363.60 KKB)(6803)

  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．

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: (2779) HTML (136) PDF (472.80 KKB)(6696)

  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.

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: (2871) HTML (165) PDF (3.92 MKB)(6682)

  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.

• 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: (2057) HTML (213) PDF (268.18 KKB)(6639)

  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: (1186) HTML (98) PDF (183.75 KKB)(6481)

  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.