Volume 42,2023 Issue 6

Infrared Materials and Devices

• High operating temperature p-on-n HgCdTe MWIR 1024×768 FPA detector

  HE Tian-Ying, QIN Qiang, KONG Jin-Cheng, QIN Gang, YANG Chao-Wei, WANG Xiang-Qian, LI Hong-Fu, WANG Qiong-Fang, LI Yong-Liang, YANG Yi-Hu, LI Yi-Min, SONG Lin-Wei, YANG Xiu-Hua, LUO Yun, CHEN Nan, HU Xu, ZHAO Jun, ZHAO Peng

  2023,42(6):711-715, DOI: 10.11972/j.issn.1001-9014.2023.06.001

  Abstract: (33) HTML (5) PDF (1.09 MKB)(81)

  Abstract:

  Increasing the operating temperature for infrared detectors is critical to reduce the size， weight and power of infrared （IR） systems. Such systems are essential to implement a compact and low-cost production of IR systems. For the Kunming Institute of Physics （KIP）， HgCdTe standard p-on-n technology with indium doping and arsenic ion implantation technology has been optimized for many years and mid-wavelength IR （MWIR） detectors with excellent electro-optical performance were realized. This paper reports the latest results of the MWIR focal plane array （FPA） detector with a high operating temperature （HOT）. Performances of the 1024×768@10 μm pitch MW detector working above 150 K were presented. The detector presenting a cut-off wavelength above 4.97 μm at 150 K has been developed. The noise-equivalent temperature difference （NETD）， dark current and operability at different operating temperatures were attained. Additionally， the IR image taken with the MWIR HgCdTe-based FPA and processed at an operating temperature of 150 K was presented and retained an operability of 99.4%.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
• Study on photocurrent transport and quantum efficiency of interband cascade infrared photodetectors

  BAI Xue-Li, CHAI Xu-Liang, ZHOU Yi, ZHU Yi-Hong, LIANG Zhao-Ming, XU Zhi-Cheng, CHEN Jian-Xin

  2023,42(6):716-723, DOI: 10.11972/j.issn.1001-9014.2023.06.002

  Abstract: (22) HTML (4) PDF (1.59 MKB)(60)

  Abstract:

  The interband cascade infrared photodetector （ICIP） can achieve high operating temperature by using the multistage cascade absorption region. But different design of absorption region will cause the mismatch of photogenerated carriers， which will affect the quantum efficiency of the device. In order to better understand the influence of the stage and thickness of ICIP on quantum efficiency， we measure the performance of ICIP based on the type-II InAs/GaSb superlattice at different operating temperatures. And based on the “average effect” of photocurrent， a quantum efficiency model operating at reverse bias voltage is established. Compared with the measured results， it is found that the experimental data and the calculated results are in good agreement at low temperatures. It is verified that the photocurrent is the average of current at all stages based on the electrical gain. However， the experimental photocurrent at high temperatures is lower than the calculation. This may be due to the short minority carrier lifetime at high temperatures， and the photogenerated carrier recombination mechanism exists at the interface of the absorption region and the relaxation region.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

  • 
  • 
  • 
  • 
  • 
  • 
• Studies of resonator-enhanced mid-infrared interband cascade light emitting diode

  ZHANG Wang-Lin, CHAI Xu-Liang, ZHOU Yi, PEI Jin-Di

  2023,42(6):724-729, DOI: 10.11972/j.issn.1001-9014.2023.06.003

  Abstract: (11) HTML (0) PDF (907.74 KKB)(52)

  Abstract:

  The mid-infrared light emitting diodes based on the interband cascade structure and resonant cavity structure are simulated and designed. Based on the traditional interband cascade LED， a distributed Bragg reflector （DBR） structure is introduced outside the device to form a resonant interband cascade LED. The parameters of the resonant cavity are simulated and optimized， including the number of DBR cycles， the length of the resonator， the position of the active region in the resonator， and the optimized device structure is obtained. The simulation results show that the device using ZnS/Ge DBR with one period as the upper mirror of the resonator has the highest output power. When the active region is located at the peak of the electric field intensity in the resonant cavity， the device will have the highest output power. The output power of the three-stage resonant cavity interband cascade LED device is equivalent to that of the 55-stage device without a resonant cavity. Meanwhile， the output light has a better direction， and the full width at half peak of the far field distribution can be reduced from 92 degrees to 52 degrees. Combined with the test results of the fabricated 5-stage interband cascade LED device， the simulation results after adding a resonant cavity structure indicate that the radiance of the peak wavelength is increased by 11.7 times， the integrated radiance is increased by 5.43 times， and the full-width at half-maximum is narrowed by 6.45 times.

  • 1
  • 2

  • 
  • 
• Bi composition-dependent study of infrared photoluminescence efficiency in InPBi bandgap

  YANG Zi-Li, WANG Man, YU Deng-Guang, ZHU Liang-Qing, SHAO Jun, CHEN Xi-Ren

  2023,42(6):730-735, DOI: 10.11972/j.issn.1001-9014.2023.06.004

  Abstract: (13) HTML (1) PDF (1.32 MKB)(37)

  Abstract:

  The photoluminescence （PL） transitions of the dilute-bismide InPBi originate mainly from the defect-related processes， and manifest the properties of long wavelength， broad linewidth and strong emission. To further clarify the PL efficiency issues， we carry out excitation power-dependent PL spectral analyses on a series of InPBi samples with different Bi compositions in this work. The PL lineshape changes significantly and the dominant emission redshifts as the Bi composition increases. Meanwhile， the excitation power-dependent evolution of the PL integral intensity indicates that the PL efficiency enhances firstly and then drops as the Bi composition rises， and reaches the maximum with a Bi composition of 0.5%. The enhancement of the PL efficiency is ascribed to the Bi trapping holes to lower the nonradioactive recombination on one hand， and to the Bi surfactant effect on the other hand. Nevertheless， the high Bi component brings excessive impurities and the Bi-related advantages are suppressed， which results in low PL efficiency. These results are beneficial to the understanding of the infrared emission performance of InPBi and suggest InPBi as a potential semiconductor for infrared optoelectronic applications.

  • 1
  • 2
  • 3

  • 
  • 
  • 
• Effects of embedded low-dimensional materials on resonant mode of distributed Bragg reflector cavity

  CUI Zhuang-Zhuang, LIU Qing-Quan, XIE Mao-Bin, WANG Shao-Wei, LU Wei

  2023,42(6):736-741, DOI: 10.11972/j.issn.1001-9014.2023.06.005

  Abstract: (12) HTML (2) PDF (1.59 MKB)(57)

  Abstract:

  Low-dimensional material embedded cavities have been widely used in nano-lasers and detectors etc. The effects of embedded materials on the cavity resonant mode need to be intensively studied for achieving the efficient coupling between the gain material and the cavity. The influences of embedded material thickness and position， cavity layer thickness and the number of distributed Bragg reflector pairs on the cavity resonant mode are discussed in this work. Results show that the cavity resonant mode changes periodically with different embedded positions and there is a maximum peak shift within a period of λ/2 optical path. The maximum peak shift decreases with increasing cavity thickness and is proportional to the embedded material thickness. The number of distributed Bragg reflector pairs does not affect the cavity resonant mode. These results provide guidance on the optical device design and the analysis of experimental phenomena， which can be applied to different wavelength ranges of distributed Bragg reflector cavity structures.

• Surface potential alignment in MoS₂ and MoTe₂ homo- and hetero-junctions

  JIANG Cong, ZHANG Shuai-Jun, LI Yu-Ying, WANG Wen-Jing, XIA Hui, LI Tian-Xin

  2023,42(6):742-746, DOI: 10.11972/j.issn.1001-9014.2023.06.006

  Abstract: (12) HTML (2) PDF (1.04 MKB)(44)

  Abstract:

  In transition metal dichalcogenides （TMD） flakes， the geometry， such as layer thickness， significantly tune the electronic properties， including bandgap， electron affinity and Fermi level. Such characteristic offers a high degree of freedom to tune the functionality of semiconductor device， once the volatile electronic properties are precisely determined. However， to date， there are still significant uncertainties in determining the Fermi-level alignment of TMD homo- or hetero- junctions， which might lead to significant deviations of band-bending and thus device performance. Here， we utilize the Scanning Kelvin Probe Microscopy （SKPM） to characterize the surface-potential/Fermi-level alignment of TMD homo- or hetero- junctions. Through this effort， a distinct phenomenon is verified where the Fermi-levels of MoS₂ and MoTe₂ shift towards the intrinsic level with an increasing layer thickness （in other words， the background doping concentration is continuously lowering）. Moreover， we show the significant impact of surface contamination （molecular scale） on the surface potential of monolayer TMD. Finally， we fabricate a MoTe₂/MoS₂ heterojunction， in which we observe the wide depletion region and large photoresponse. Together， those findings might offer a reference to precisely stack van der Waals （vdW） layers as designed for both electronic and optoelectronic applications.

Terahertz and Millimeter Wave Technology

• Research on watt-level power combining technology at terahertz band based on bonding wire compensation

  ZHU Xiang, ZHANG Jun-Jie, CHENG Hai-Feng, GUO Jian, SHI Yong-Rong, WANG Wei-Bo

  2023,42(6):747-754, DOI: 10.11972/j.issn.1001-9014.2023.06.007

  Abstract: (14) HTML (0) PDF (2.96 MKB)(43)

  Abstract:

  With the application demands of solid-state high power in the terahertz （THz） band， a THz-band watt-level power output is achieved by adopting GaN power amplifier （PA） MMIC and power combining technology. Microstrip-waveguide transition， and the low-loss interconnection based on the gold wire compensation are used to package a PA module composed of two PA MMICs and an E-plane T-junction two-way power splitter/combiner. Maximum output power of 160 mW is achieved. Based on the module and an eight-way E-plane combiner， a sixteen-way power combining amplifier is designed across the frequency range of 180 to 238 GHz. Output power of more than 300 mW is achieved with +10 V drain voltage， and the maximum power is 1.03 W at 189 GHz.

• Faraday rotation in nitrogen-doped diamond measured by polarized terahertz time-domain spectroscopy in the presence of strong magnetic field

  XIAO Huan, WEN Hua, XU Wen, ZHANG Jing, CHENG Xing-Jia, XIAO Yi-Ming, DING Lan, LI Hao-Wen, CHENG Yan-Zhe, HE Bin

  2023,42(6):755-761, DOI: 10.11972/j.issn.1001-9014.2023.06.008

  Abstract: (22) HTML (2) PDF (1.01 MKB)(39)

  Abstract:

  Nitrogen （N）-doped diamond （N-D） is one of the most important carbon-based electronic materials and has many interesting and unique features in terms of physics owing to the presence of N related color centers. In this paper， the terahertz （THz） magneto-optical （MO） properties of N-D grown by microwave plasma chemical vapor deposition （MPCVD） are investigated. By using polarized THz time-domain spectroscopy （TDS） in the presence of magnetic field from 0 to 8 T， the THz transmission through an N-D sample in Faraday geometry is measured at 80 K. The dependence of the Faraday rotation angle and ellipticity， the complex transverse or Hall MO conductivity and the complex dielectric constant upon the magnetic field for N-D are examined. The results show that N-D has excellent THz MO Faraday rotation effect and can be applied as THz rotatory material.

  • 1
  • 2
  • 3
  • 4
  • 5

  • 
  • 
  • 
  • 
  • 
• Progress in the study of nonlinear dynamic characteristics based on quantum cascade lasers

  FENG Wei, MAO Yu, MENG Yue, RENG Tian-Liang, WANG Chang, CAO Jun-Cheng

  2023,42(6):762-770, DOI: 10.11972/j.issn.1001-9014.2023.06.009

  Abstract: (17) HTML (1) PDF (1.12 MKB)(38)

  Abstract:

  Quantum Cascade Laser （QCL） is a unipolar semiconductor laser that relies on the excitation of photons radiated by electrons leaping between subbands of quantum wells. Numerous theoretical and experimental studies have demonstrated that slight external perturbations （optical feedback， optical injection） or sufficiently strong internal nonlinear mode couplings can induce nonlinear output of semiconductor lasers. QCL， as a new type of semiconductor device， is characterized by high intracavity strength， strong inter-subband optical nonlinearity and fast electron relaxation time， which has stimulated the interest in studying its nonlinear dynamics. In this paper， we review in detail the progress of the study of nonlinear dynamical characterization in QCL， explore the mechanism of the generation of nonlinear dynamical properties of QCL， and summarize the applications of nonlinear properties of QCL.

  • 1
  • 2
  • 3

  • 
  • 
  • 
• Design of the integrated interaction circuits for a 200-kW Ka-band klystron with two output ports

  BI Liang-Jie, JIANG Xin-Yu, LI Hai-Long, WANG Bin, MENG Lin, YIN Yong

  2023,42(6):771-778, DOI: 10.11972/j.issn.1001-9014.2023.06.010

  Abstract: (7) HTML (0) PDF (1.34 MKB)(33)

  Abstract:

  In this paper， an efficient resonant circuit based on integrated interaction units is proposed to improve the beam-wave interaction for increasing the peak power of a Ka-band klystron to 200 kW. The integrated-unit circuit is designed with connecting two or several single-beam-wave interaction units across the cross section （each of which is typically used in a conventional single-beam klystron） based on the cascaded field structure in the rectangular gap waveguide with specific fusion boundary conditions. For the input cavity， two interaction units have been efficiently integrated to obtain the optimal absorption efficiency with the constant input power at ~35 GHz， through optimizing both the beam-loading parameters and cavity parameters. The output cavity has been 1） designed with two output ports for balancing the effect of the power extraction on the integrated circuit， and 2） optimized to deliver 200-kW peak power through injecting two pre-modulated beams. The overall interaction circuit of a Ka-band klystron is accordingly designed to produce the peak power of 202.9-kW with the efficiency of 40.2% and the maximum gain of 47 dB using particle-in-cell （PIC） simulations， when the two beams with the voltage of 45 kV and every current of 5.6 A are used to drive the klystron.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
• Enhanced terahertz wave generation in air-plasma induced by femtosecond three-color harmonic pulses

  WANG Han-Qi, FAN Wen-Hui, CHEN Xu, YAN Hui

  2023,42(6):779-787, DOI: 10.11972/j.issn.1001-9014.2023.06.011

  Abstract: (11) HTML (0) PDF (1.15 MKB)(43)

  Abstract:

  The generation of terahertz waves from air-plasma induced by femtosecond three-color harmonic pulses with a frequency ratio of 1：2：m （m is a positive integer）， based on the transient photocurrent model and the sawtooth-like electric field formed via multi-color harmonic pulses superposition， has been theoretically investigated. It can be seen that when the air is saturated ionized and the electron density reaches the same maximum， for the same number of harmonic pulses， terahertz conversion efficiency is not always higher when the electric field shape in the composed pulse envelope is closer to a sawtooth waveform and more asymmetric. Besides， the specific wavelength combination schemes of femtosecond three-color harmonic pulses with the frequency ratios of 1：2：3 and 1：2：4 have also been simulated， which can significantly enhance the generation of terahertz waves， and are realized by adding only a set of optical parametric amplifiers on the basis of the conventional two-color laser pulse case at the frequency ratio of 1：2. Our study will be helpful to obtain intense terahertz sources and provide guidance for experimental operations.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
• From terahertz to mid-infrared ultra-broadband radiation generated from few-cycle laser pulse interaction with gas plasma filament

  DU Hai-Wei, WANG Jing-Yi, SUN Chang-Ming, LI Qiang-Shuang

  2023,42(6):788-794, DOI: 10.11972/j.issn.1001-9014.2023.06.012

  Abstract: (6) HTML (0) PDF (1.66 MKB)(45)

  Abstract:

  The strong few-cycle laser pulse interaction with the gas plasma filament can generate strong and broadband terahertz radiation. Here， we investigate the detail of plasma current and its terahertz radiation produced by the few-cycle laser pulse interaction with the gas plasma based on the calculations. The ionization during the plasma filamentation is in the transition between the tunnel ionization and the multiphoton ionization. The results show that this scheme can generate ultra-broadband radiation from the range of terahertz to mid-infrared， and its amplitude is a periodic function of the carrier-envelope phase of the few-cycle laser pulse. The frequency of the terahertz pulse is determined by the duration of the laser pulse， the time evolution of ionization and the plasma current， rather than by the density of the plasma. This work might give a useful clue to carry out the experiment of ultra-broadband terahertz generation by the few-cycle laser pulse interaction with the gas plasma filament.

• Single mode terahertz quantum cascade lasers based on distributed Bragg reflector

  BAI Hong-Zhou, ZANG Shan-Zhi, TAN Cheng, WANG Kai, GAN Lianghua, XU Gang-Yi

  2023,42(6):795-805, DOI: 10.11972/j.issn.1001-9014.2023.06.013

  Abstract: (10) HTML (0) PDF (1.72 MKB)(37)

  Abstract:

  In the conventional semiconductor distributed Bragg reflector （DBR） lasers， to obtain stable single mode emission， the gain section should be short enough to make the free spectrum range larger than half of the bandwidth of the reflection plateau caused by the DBR. This constraint severely limits the threshold and the output power of the lasers. In this work， single mode terahertz DBR quantum cascade lasers （THz-DBR-QCLs） that break the above constraint are realized. The lasers are based on the ridge waveguide， and exploit a cleaved facet and a DBR mirror to construct the resonator. Exploiting the intrinsic narrow gain spectrum of the THz-QCL， we tailor the reflection spectrum of the DBR so that the high reflection plateau and the gain spectrum are partially overlapped， obtaining the THz-QCLs with single mode emission. Such strategy enables single mode emission with a significantly elongated gain section， far beyond the constraint of the free spectrum range. In experiments， we realize the single mode THz-DBR-QCLs， whose gain section is as long as 3.6 mm. The emission frequency is about 2.7 THz， and the side mode suppression ratio （SMSR） exceeds 25 dB. The measured threshold and temperature characteristics of the THz-DBR-QCLs are comparable to the Fabry-Perot THz-QCLs fabricated with the same material. Our work suggests a novel approach to realize the high performance single mode THz-QCLs.

  • 1

  • 
• A review on Terahertz lens antennas

  CHEN Yi-Cong, WANG Shuo-Bo, ZHAI Guo-Hua, GAO Jian-Jun

  2023,42(6):806-814, DOI: 10.11972/j.issn.1001-9014.2023.06.014

  Abstract: (15) HTML (6) PDF (1.19 MKB)(62)

  Abstract:

  Terahertz （THz） antenna is an indispensable component of the future 6G mobile communication， among which THz lens antenna has attracted extensive attention due to the merits of high gain， stable radiation performances， low cost etc. The THz lens antennas can operate without suffering from the problem of feeding occlusion， they can also realize the functions of beam control. The function of focusing can not only be applied in the imaging system， but also play the role of collimation in the test devices. The advancement of THz fabrication technology makes the THz lens antenna more precise and effective， which further promotes the development of the THz lens antenna. In this review， the THz lens antennas reported in the last five years are summarized by synthesizing their features such as functions， fabrication processes， morphologies， and applications.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 

Infrared Spectroscopy and Spectral Analysis

• Novel local calibration optimization from soil mid-infrared spectral library

  SHEN Jia-Li, CHEN Song-Chao, HONG Yong-Sheng, LI Shuo

  2023,42(6):815-823, DOI: 10.11972/j.issn.1001-9014.2023.06.015

  Abstract: (8) HTML (2) PDF (2.34 MKB)(28)

  Abstract:

  Soil mid-infrared （MIR） can provide a rapid， non-polluting， and cost-efficient method for estimating soil properties， such as soil organic carbon （SOC）. Although there is a wide interest in using the soil spectral library （SSL） for soil analysis at various scales， the SSL with a general calibration often produces poor predictions at local scales. Therefore， developing methods to ‘localize’ the spectroscopic modelling is a reliable way to improve the use of SSL. In this study， we proposed a new approach that aims to rapidly build the optimal local model from the SSL by calculating the spectral similarity and developing the local calibration， in order to further improve the prediction accuracy. The distance matrix was constructed by three distance algorithms， namely Euclidean distance， Mahalanobis distance， and Cosine distance， which were compared and used to measure the similarity between the local samples and the SSL. The capacity curve， which was taken from the distance matrix， was used with a method called “continuum-removal” to find the feature points. Partial least-squares regression was used to build the spectroscopic models for SOC estimation. We found that for all three distance algorithms combined with the continuum-removal， the local calibration derived from the first feature point gave us a good idea of how accurate the prediction would be. The Mahalanobis distance can effectively develop the optimal local calibration from the MIR SSL， which not only achieved the best accuracy （R² = 0.764， RMSE = 1.021%） but also used the least number of samples from SSL （14% SSL）. On local scales， the approach we proposed can significantly improve both the analytical cost and the accuracy of the soil MIR technique.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

  • 
  • 
  • 
  • 
  • 
  • 
• Research on hyperspectral image classification method based on deep learning

  ZHANG Bin, LIU Liang, LI Xiao-Jie, ZHOU Wei

  2023,42(6):824-832, DOI: 10.11972/j.issn.1001-9014.2023.06.016

  Abstract: (13) HTML (1) PDF (1.14 MKB)(37)

  Abstract:

  Targeting the issue of insufficient accuracy of hyperspectral image classification methods， a hyperspectral image classification method based on Spatial-spatial transformer （SST） network is proposed. Firstly， the hyperspectral images are preprocessed into one-dimensional feature vectors. Then， the SST hyperspectral image classification network with spectral-spatial attention module and pooled residual module is designed. The overall classification accuracy of the proposed classification method on Indian Pines dataset and Pavia University dataset is 98.67% and 99.87%， respectively， which indicates that this method has high classification accuracy and provides a new scheme for hyperspectral image classification and application.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
• Evaluation of observation quality of FY-3E/HIRAS-II using the innovation vector method

  CHEN Hong-Tao, GUAN Li

  2023,42(6):833-842, DOI: 10.11972/j.issn.1001-9014.2023.06.017

  Abstract: (11) HTML (0) PDF (1.47 MKB)(43)

  Abstract:

  FY-3E/HIRAS-II is the first early mooring orbiting infrared hyperspectral instrument in the world. Evaluating the quality of its observation data plays a very important role in improving the data assimilation and the accuracy of global numerical weather prediction. Based on the 35 days of HIRAS-II observations from December 2021 to January 2022 and March 2022， this paper uses the innovation vector method to assess the quality of the on-orbit observation data. The distribution characteristics of O-B deviation and standard deviation are calculated by land and ocean respectively. Further matching MetOp-B/IASI observation data in the same time period and in the same region， the double-difference method is used to analyze the quality of HIRAS-II observation data， which can eliminate the influence of radiation transfer mode simulation deviation. The results show that the O-B average deviation of long wave and medium wave in most channels is less than 0.5 K， and the standard deviation is within 1 K. The standard deviation on land is larger than that on ocean （especially for window channels）. Due to the deviation of ERA5 reanalysis data， the radiation value simulated by RTTOV has a systematic error in the 664-665 cm^-1 CO₂ absorption band and the 1 300-1 680 cm^-1 water vapor absorption band， which makes the deviation larger， and the double O-B bias in these bands compared with MetOp-B/IASI is close to 0 K， indicating that the O-B bias is mainly caused by the simulation error of the radiation transfer mode， rather than the low quality of the instrument observation. The large deviation near the 980-1 080 cm^-1 O₃ absorption band and the 1 300 cm^-1 CH₄ absorption band is caused by the use of fixed climate profile values in RTTOV. The O-B average deviation of short wave in most channels is between -2 K and 2 K， and the standard deviation is within 2 K. The channels near 1 920 cm^-1 are the junction of medium wave and short wave of the instrument， so different detectors will cause large O-B deviation. The large deviation of 2 267-2 380 cm^-1 due to the fact of the NLTE effect （Non-local Thermodynamic Equilibrium） is not taken into account when RTTOV simulates the brightness temperature. The deviation and standard deviation of channels greater than 2 400 cm^-1 increase gradually due to solar pollution. HIRAS-II O-B deviation is asymmetric with the scanning angle， so it is necessary to correct the scanning angle deviation when using HIRAS-II data.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 

Remote Sensing Technology and Application

• An infrared zoom imaging system with large zoom ratio based on linear motion mechanism

  ZHOU Pan-Wei, YU Yang, LI Fan-Ming, YE Xi-Sheng

  2023,42(6):843-850, DOI: 10.11972/j.issn.1001-9014.2023.06.018

  Abstract: (8) HTML (0) PDF (1.91 MKB)(44)

  Abstract:

  In order to meet the urgent need of large-scale search and accurate target recognition， an infrared zoom imaging system with large zoom ratio is developed. Two independently moving zoom lenses and one compensating lens are designed， the large zoom ratio can be obtained by the cascade of two zoom lenses. According to the characteristics of multiple moving lenses and complex zoom curves， the zoom motion is realized by linear motion mechanism， and driven by linear motor integrated encoder and thread screw rod. The mechanical analysis of the system is carried out by the finite element simulation， and the maximum displacement of the lenses is 3.04×10^-3 mm. The imaging system is suitable for the medium-wave infrared cooled 640×512 focal plane area-array detector， and the zoom ratio is 55. The results of laboratory imaging and outfield imaging show that the system has a clear and good imaging quality with a continuous change in focal length from 6 mm to 330 mm， which verifies the performance of the system. The design is reasonable and reliable. The research findings of this paper have broad application prospects in search， tracking， reconnaissance， and surveillance.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
• A self-calibration method of the boresight angles of airborne hyperspectral VNIR/SWIR modules

  GUO Ran, WANG Yue-Ming

  2023,42(6):851-862, DOI: 10.11972/j.issn.1001-9014.2023.06.019

  Abstract: (10) HTML (0) PDF (6.18 MKB)(45)

  Abstract:

  External field-of-view （FOV） stitching is an effective way to achieve an airborne hyperspectral imaging system with both a large field-of-view and a wide spectral sampling range. However， due to the independent installation of each module， the boresight angles between the corresponding VNIR module and SWIR module will change after a long period of equipment operation， and the change of boresight angles will negatively affect the data fusion effect. The overlap of FOV makes the calibration method based on the epipolar geometry and homography constraints ineffective in solving the boresight angles between the corresponding VNIR/SWIR modules. In this paper， an algorithm based on the reprojection error is proposed for an airborne hyperspectral imaging system with external field-of-view stitching to achieve self-calibration of the boresight angles and focal length between the VNIR/SWIR backends. The algorithm has been applied to the Airborne Multi-Modality Imaging Spectrometer （AMMIS）. Experimental results show that the average error of the method is less than 0.2 pixels， and it is also well adapted to tilt-placed modules.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 

Infrared Photoelectric Technology and Application

• The photon detection mode and performance analysis of SiPM photon counting Lidar under different discrimination thresholds

  LIU Xin-Yuan, XIAO Yi, MA Yue, XIANG Yu-Yan, GUO Gao-Feng, WANG Jia-Wei, HUANG Wei-Yi, TAN Chong-Tao, LI Song

  2023,42(6):863-873, DOI: 10.11972/j.issn.1001-9014.2023.06.020

  Abstract: (13) HTML (2) PDF (1.85 MKB)(46)

  Abstract:

  Silicon photomultiplier （SiPM）is a silicon array structure based on the Geiger mode avalanche photodiode. It not only has extremely high photon counting sensitivity and response speed， but also has the characteristics of high dynamic range and linear response under the multi-photon condition， which makes it have unique advantages in the application of photon counting LIDAR. However， due to the multi-pixel， single-time channel working mode of SiPM， its output voltage has a greater probability of pulse pile up compared with other single-photon detectors. Therefore， the detection process of SiPM under different discrimination thresholds is more complicated. To solve this problem， a SiPM photon event response model is established in this paper. Based on this， the time-domain distributions of the shielding effect and the triggering effect caused by pulse pile up are discussed. Finally， the semi-analytic detection probability and false alarm probability models of SiPM are established. At the same time， a photon counting Lidar system based on SiPM detector is built， and the theoretical model is verified by observing that the measured output voltage waveform and point cloud distribution are consistent with the theoretical model （R²>0.95）. Furthermore， the distribution of SiPM photon point cloud with different discrimination thresholds is quantitatively evaluated by the recall and precision ratio， and the optimal discrimination threshold interval is given， which has important guiding significance for the design and theoretical analysis of photon counting Lidar system based on SiPM.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7

  • 
  • 
  • 
  • 
  • 
  • 
  • 
• Analysis of the operating distance of infrared polarimetric imaging system considering the non-ideality of the detector

  TAN Chang, WANG Shi-Yong, GAO Si-Li

  2023,42(6):874-882, DOI: 10.11972/j.issn.1001-9014.2023.06.021

  Abstract: (11) HTML (1) PDF (897.81 KKB)(49)

  Abstract:

  To compare the detection capabilities of traditional infrared imaging systems and infrared polarization imaging systems， the operating distance models of the systems were established based on the minimum resolvable temperature difference and the minimum resolvable polarization degree difference. The effects of parameters of non-ideal detectors on the detection capabilities of the systems were discussed， and the corresponding experiments were designed to verify the reliability of the established models. This provides a reference for the selection of imaging systems in different application scenarios in actual detection.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7

  • 
  • 
  • 
  • 
  • 
  • 
  • 
• A 0.3 W@4.2 K high-capacity lightweight cryogenic system for space BIB detection

  CHU Jin-Jian, LIU Shao-Shuai, WANG Peng, DING Lei, XIAO Yun-Long, YIN Wang, CHEN Zhi-Chao, SHA Xin-Quan, JIANG Zhen-Hua, WU Yi-Nong

  2023,42(6):883-894, DOI: 10.11972/j.issn.1001-9014.2023.06.022

  Abstract: (9) HTML (1) PDF (1.79 MKB)(29)

  Abstract:

  Large-array BIB detectors have been the subject of extensive research due to their high quantum efficiency and low dark current， particularly for space applications such as the JWST， which was launched in 2021 and has made numerous significant astronomical observations. A stable， efficient， and lightweight temperature zone liquid helium cryogenic system is essential to the operation of the BIB detectors. The helium JT cryocooler is a trend that aims to meet the cooling requirements of a liquid helium temperature zone in space while supplanting the traditional， large-volume liquid helium dewar. To simultaneously increase the cooling capacity at 4.2 K and reduce its weight， a high-capacity， lightweight 4.2 K cryocooler with a cooling power of 0.3 W@4.2 K is proposed. Experiments on the previous 0.1 W at 4.1 K prototype of the cryogenic system have validated the system''s design method. Different cooling methods are used in different cooling temperature zones to achieve the efficiency and lightness of cooling. A new integrated Stirling cryocooler was developed to provide efficient pre-cooling at 80 K， with a cooling capacity of 15 W and a weight of only 4.5 kg. A 0.9 W at 15 K active piston phase-shifting pulse tube cryocooler is used to improve the efficiency of the second-stage pre-cooling. The developing cryogenic system can provide a cooling capacity of 0.3 W at 4.2 K with a power consumption of less than 1.8 kW by coupling the helium JT cycle. It will provide the essential guarantee for the large-scale BIB detection required for infrared astronomical observation， which is undergoing rapid development.

  • 1
  • 2
  • 3
  • 4

  • 
  • 
  • 
  • 
• Clinical research progress on the fluorescence imaging in the second near-infrared window

  NI Hu-Wei, QIAN Jun

  2023,42(6):895-905, DOI: 10.11972/j.issn.1001-9014.2023.06.023

  Abstract: (9) HTML (0) PDF (1.52 MKB)(56)

  Abstract:

  The near-infrared fluorescence imaging is a vital technology that enables the image-guided surgery. In recent years， the maturation of the optical bioimaging theory in the second near-infrared window （NIR-II， 900-1 700 nm） has led to the emergence of NIR-II fluorescence imaging as a significant research area in the imaging-guided surgery. This paper provides a succinct overview on the current development state of NIR-II fluorescence probes and imaging systems based on the NIR-II optical bioimaging theory. Furthermore， it reviews the studies conducted on the NIR-II fluorescence imaging in the small animal and clinical surgery， and discusses the potential and challenges of this technology in the clinical surgery， including the difficulties that need to be addressed in the future clinical translation.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 

Image Processing and Software Simulation

• Depth estimation of thermal infrared images based on self-supervised learning

  DING Meng, GUAN Song, LI Shuai, YU Kuai-Kuai, XU Yi-Ming

  2023,42(6):906-915, DOI: 10.11972/j.issn.1001-9014.2023.06.024

  Abstract: (9) HTML (0) PDF (1.11 MKB)(32)

  Abstract:

  Depth estimation based on unsupervised learning is one of the important issues in the field of computer vision. However， existing algorithms of depth estimation are mainly designed based on visible images. Compared with visible images， thermal infrared images have the disadvantages of low contrast and insufficient detailed information. To this end， a depth estimation network is constructed and an unsupervised depth estimation method is proposed for thermal infrared images according to their characteristics. The network consists of three parts： feature extraction module， feature aggregation module， and feature fusion module. Firstly， a feature aggregation module is designed to improve network ability to acquire the edge information of target objects and the small object information of the image. Secondly， the channel attention mechanism is introduced in feature fusion module to effectively capture the interaction relationship between different channels. Finally， a depth estimation network for thermal infrared images is established. In this network， the model parameters are trained by thermal infrared sequence images to achieve the pixel-level depth estimation of a single thermal infrared image. The results of ablation studies and comparative experiments fully demonstrate that the performance of the proposed method in pixel-level depth estimation of thermal infrared image outperforms other representative methods.

• An unsupervised few-shot infrared aerial object recognition network based on deep-shallow learning graph model

  LI Yu-Ze, ZHANG Yan, CHEN Yu, YANG Chun-Ling

  2023,42(6):916-923, DOI: 10.11972/j.issn.1001-9014.2023.06.025

  Abstract: (19) HTML (3) PDF (3.63 MKB)(39)

  Abstract:

  In the field of military aerial object recognition， due to the lack of samples， current artificial intelligence algorithms cannot perform well. This paper uses the existing sufficient auxiliary domain images to assist the application domain with few samples for cross-domain object recognition and solves the problem of weak generalization ability and poor performance of the recognition model caused by missing labels and sparse samples. A cross-domain object recognition algorithm named Deep-Shallow Learning Graph Model （D-SLGM） is proposed. Firstly， a deep-shallow two-stream feature extraction algorithm is proposed to solve the problem of feature representation under unsupervised few-shot conditions. At the same time， a feature fusion algorithm based on graph model is proposed to realize high precision fusion between features. Then， a recognition model is trained based on the fused features， the generalization ability of the algorithm is improved. The self-built aerial object dataset is adopted with three application scenarios. The experimental results show that the mean average recognition accuracy of D-SLGM reaches 78.2%， which is better than those of the comparison methods. D-SLGM has great potential in actual aerial object recognition applications.

• A whole chain automatic simulation method for the on-orbit stray light effect of optical payloads

  YIN Kai, NIU Xin-Hua, ZHANG E

  2023,42(6):924-930, DOI: 10.11972/j.issn.1001-9014.2023.06.026

  Abstract: (9) HTML (4) PDF (1.42 MKB)(36)

  Abstract:

  The temperature inversion inconsistency phenomenon is analyzed for the on-orbit IR calibration of Visible and InfraRed Radiometer （VIRR） which is a payload onboard polar-orbiting meteorological satellite FY-3C. A specific methodology， i.e.， the whole chain automatic simulation and analysis， is proposed. This method involves the orbital parameters and the satellite platform environment. By means of the ray trace of the opto-mechanical structure with high precision， the quantified effect of solar stray light is obtained. The simulation includes on-orbit IR calibration and solar incidence， resulting in the identification of the incidence path of solar stray light as well as the explanation for the temperature inversion inconsistency. Through the comparison between the simulated results and the on-orbit data of the satellite， the effectiveness and the validity of the method are verified. This method can be applied to the simulation and analysis of on-orbit stray light effect of the same-typed payloads. This work can also provide references to the recalibration of historical data.

  • 1
  • 2
  • 3

  • 
  • 
  • 
• Coronene enhanced CMOS image sensor

  LUO Lei, SONG Li-Yuan, TANG Li-Bin, WANG Shan-Li, CAI Yu-Hua, LI Jun-Bin

  2023,42(6):931-936, DOI: 10.11972/j.issn.1001-9014.2023.06.027

  Abstract: (9) HTML (2) PDF (1.30 MKB)(36)

  Abstract:

  The responsiveness of typical silicon-based CMOS image sensors in the UV band is not high due to the limited penetration depth of UV light in silicon and the absorption of UV light by poly silicon gates. A low-cost down-conversion method was used in this work to enhance the UV response of a CMOS image sensor. Vacuum thermal evaporation was used to deposit coronene films on quartz substrates and CMOS image sensors， respectively. The films'' optical characteristics，infrared spectrum，light stability，and thermal stability were investigated. The experimental results reveal that the Coronene coating absorbs UV light and emits green fluorescence at 500 nm，which closely matches the spectral response peak of the CMOS image sensor. At the same time，it is found that the experimental value of the infrared absorption spectrum of Coronene is in good agreement with the calculated value，and the fluorescence intensity of the emission peak remained 95.7% after the film was annealed at 200 ℃ for 20 minutes. After approximately 60 minutes of exposure at 280 nm excitation wavelength，the fluorescence intensity decreased exponentially to 64% of the initial value. The UV enhancement effect of the film was qualitatively analyzed by the CMOS monochromatic camera under visible light（400-780 nm） and ultraviolet light （365 nm） radiation. It is found that the sensitivity of the CMOS monochromatic camera to UV light can be improved after the deposition of Coronene film.

红外及光电技术与应用

• Real time denoising method for spaceborne photon counting laser ranging radar

  TAN Chong-Tao, YU Wen-Bo, XIANG Yu-Yan, LI Shao-Hui, YU Jing, WANG Qian-Ying, LI Song

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

  Abstract: (51) HTML (4) PDF (2.29 MKB)(28)

  Abstract:

  The spaceborne photon counting laser ranging radar system has significant advantages such as high repetition rate and high precision， but it also faces the problem of large amount of original data and high proportion of noise data. In order to adapt to the transmission capacity of the satellite data channel， it is necessary to compress the original data volume and ensure the recall rate of signal photons， so it is necessary to develop a hardware based real-time denoising algorithm. This article proposes a fast denoising algorithm that combines coarse and fine processing. Firstly， based on the laser emission pulse width， system noise rate， target characteristics， and local density information of received photon events， coarse denoising is performed to remove some noisy photons； Then， using histogram statistics， fine denoising is performed on the retained photon events to determine the signal photon interval and the final signal photon and its time information. The algorithm is verified by Monte Carlo simulation and ICESat-2 measured data. The test results show that the recall ratio， precision ratio and harmonic average of the algorithm are more than 94%， 93% and 94% respectively， and the operation efficiency is improved by 10%. The algorithm can achieve fast and real-time denoising of photon events， providing a theoretical basis for real-time denoising processing of onboard hardware.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8

  • 
  • 
  • 
  • 
  • 
  • 
  • 
  • 

太赫兹与毫米波技术

• InGaAs/InAlAs InP-based HEMT with the current cutoff frequency 441 GHz

  FENG Rui-Ze, CAO Shu-Rui, FENG Zhi-Yu, ZHOU Fu-Gui, LIU Tong, SU Yong-Bo, JIN Zhi

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

  Abstract: (43) HTML (0) PDF (1.15 MKB)(92)

  Abstract:

  In this letter， an In_0.53Ga_0.47As/In_0.52Al_0.48As InP-based HEMT with f_T > 400 GHz was designed and fabricated successfully. A narrow gate recess technology was used to optimize the parasitic resistances. The gate length is 54.4 nm， and the gate width is 2 × 50 μm. The maximum drain current I_DS.max is 957 mA/mm， and the maximum transconductance g_m.max is 1265 mS/mm. The current gain cutoff frequency f_T is as high as 441 GHz and the maximum oscillation frequency f_max reaches 299 GHz， even at a relatively small value of V_DS = 0.7 V. The reported device can be applied to terahertz monolithic integrated amplifiers and other circuits.

• Structural design of mid-infrared waveguide detectors based on InAs/GaAsSb superlattice

  PEI Jin-Di, CHAI Xu-Liang, WANG Yu-Peng, ZHOU Yi

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

  Abstract:

  In the near-infrared, spectroscopic detection of molecules has been achieved using on-chip waveguides and resonators. However, in the mid-infrared band, many sensors still rely on off-chip light sources and detectors, which limit the integration and sensitivity of chemical sensing chips. Here, we demonstrate an InAs/GaAsSb superlattice mid-infrared waveguide integrated detector. The GaAsSb waveguide layer and the InAs/GaAsSb superlattice absorbing layer are coupled via the evanescent coupling, enabling low-loss and high-performance mid-infrared light detection. We simulated the photoelectricity characteristics of the device, analyzed the factors influencing the integration of the InAs/GaAsSb superlattice photodetector and the GaAsSb waveguide. Optimal thicknesses and lengths for the absorption layer are determined. With minimal noise equivalent power, the quantum efficiency can reach 68.9%. The waveguide detector based on Ⅲ-V materials is easier to integrate mid-infrared light source and realize the on-chip photoelectric detection chip.

  • 1
• Characteristics Analysis of 1.06um Long-cavity Diode Lasers Based on Asymmetric Waveguide Structures

  ZHAO Ren-Ze, GAO Xin, FU Ding-Yang, ZHANG Yue, SU Peng, BO Bao-Xue

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

  Abstract:

  In long-cavity edge-emitting diode lasers, longitudinal spatial hole burning (LSHB), two-photon absorption(TPA) and free carrier absorption(FCA) are among the key factors affecting the linear increase in output power at high injection currents. In this paper, a simplified numerical analysis model is proposed for 1.06um wavelength long-cavity diode lasers by combining TPA and FCA losses with one-dimensional(1D) rate equations. The effects of LSHB, TPA and FCA on the output characteristics are systematically analyzed, and it is proposed that the front facet reflectivity and the position of the quantum well(QW) in the waveguide can be adjusted to improve the front facet output power.

  • 1
• Terahertz imaging super-resolution algorithm based on spatial curve filling

  YANG Mo-Xuan, ZHAO Yuan-Meng, LIU Hao-XIN, LIU Yi, WU You, ZHANG Cun-Lin

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

  Abstract:

  The performance of radiation sources and detectors currently limits terahertz imaging technology, which still requires further improvement in terms of detail resolution, imaging speed, and noise suppression. This paper proposes a terahertz image super-resolution algorithm based on spatial curve filling. The ViT (Vision Transformer) structure backbone network is utilized to extract terahertz image features through an attention mechanism. A Hilbert spatial curve is constructed to reconstruct the image according to the feature map using the curve filling method. Lightweight one-dimensional convolution processing is used for reconstructing image features, while inverse transformation of reconstructed maps restores the image"s spatial structure. Finally, pixel reorganization enables upsampling to obtain an output image with enhanced object contour and details. Experimental results show that compared with conventional ViT structures, this proposed method improves Peak Signal-to-Noise Ratio (PSNR) by 0.81 dB and Structural Similarity Index (SSIM) by 0.0074 effectively suppressing noise influence on texture while significantly improving resolution resulting in images with improved quality.

  • 1
• An improved ASM-HEMT model for kink effect on GaN microwave devices

  WANG Shuai, CHENG Ai-Qiang, GE Chen, CHEN Dun-Jun, LIU Jun, DING Da-Zhi

  Abstract: (5) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  With the analysis of experiment and theory on GaN HEMT devices under DC sweep, an improved model for kink effect based on ASM-HEMT is proposed, considering the relationship between the drain/gate-source voltage and kink effect. The improved model can not only accurately describe the trend of the drain-source current with current collapse and kink effect, but also precisely fit different values of drain-source voltages at which kink effect occurs under different gate-source voltages. Furthermore, it well characterizes the DC characteristics of GaN devices in the full operating range, with the fitting error less than 3%. To further verify the accuracy and convergence of the improved model, a load-pull system is built in ADS. The simulated result shows that although both the original ASM-HEMT and the improved model can predict the output power of GaN devices well, the improved model predicts the efficiency more accurately, 4% higher than the original ASM-HEMT.

  • 1
• Metalens for polarization-switchable multi-functions multiplexing in multiple channels

  LIU Xiao-Dong, ZHU Yi-Ming

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

  Abstract:

  Metasurfaces provide a new platform for studying planar and ultrathin optical components. The traditional geometric-phase-based metalens are limited to the polarization locking, which inevitably hinders its function in multiplexing of multiple functions. Herein, an approach based on geometric phase is proposed to realize polarization decoupling of metalens. This method can be applied to design metalens that enables functionalities of polarization switchable multi-functions(focusing and vortex beam etc...) multiplexing in the longitudinal direction or both the longitudinal and transverse directions. The results provide a new avenue for multifunctional integrated planar components.

  • 1
• A simplified parameterization scheme of mid-infrared radiative transfer for satellite remote sensing

  YAO Qian, XU Hua, FAN Cheng, LI Li, WANG Si-Heng, ZHENG Yang, XU Wen-Bin, HOU Wei-Zhen, XU Jing-Hai, ZHUANG Qi-Feng, ZHOU Peng, ZHANG Hao, CHEN Zhen-Ting, LI Zheng-Qiang

  Abstract: (44) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  As the connecting spectral band of visible-near infrared and thermal infrared, mid-infrared (MIR) combines the reflective characteristics of short-wave radiation and the emissive characteristics of long-wave radiation, which is of great importance for application scenarios such as temperature detection and target identification. At present, the radiative transfer (RT) calculation of the MIR spectrum still faces the problem of many input background parameters which are not easy to obtain. Based on this, a simplified parameterization scheme of MIR RT for satellite remote sensing is proposed. Using the MODTRAN model (MM), the background surface and atmospheric parameters involved in the MIR daytime RT process were quantitatively simulated and analyzed to obtain the key parameters affecting RT, from which an MM-based parameter simplified scheme (SS) is developed. The total radiance calculated by SS and MM are compared and validated at the center wavelength of 6 MIR channels of MODIS, and the RMSE is less than 0.004399 with high accuracy. SS only relies on surface temperature, surface emissivity, atmospheric profile type, water vapor and cloud optical thickness, and does not require input of aerosol, CO2 and O3 data. Compared with MM, SS reduces the input parameters from 8 categories to 5 categories, and the calculation time efficiency increases by 9.02%. With limited computational resources, the SS proposed in this paper can provide support for the application areas such as fast processing of MIR images and remote sensing simulation of large scenes.

  • 1
• A 66-to-112.5 GHz low noise amplifier with minimum NF of 3.9 dB in 0.1-μm GaAs pHEMT technology

  LI Ze-Kun, CHEN Ji-Xin, ZHENG Si-Dou, HONG Wei

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

  Abstract:

  A wideband low noise amplifier (LNA) covering the whole W-band in 0.1-μm GaAs pHEMT technology is designed. To reduce the inter-stage crosstalk and obtain wideband matching, a bypass circuit composed of dual shunt capacitors is proposed to provide wideband RF grounding. The wideband input matching and optimal noise matching are implemented by a dual-resonance input matching network. The measurement results exhibit a peak gain of 20.4 dB at 108 GHz. The measured small signal gain is 16.9 to 20.4 dB across 66 to 112.5 GHz. The measured noise figure (NF) is 3.9 dB at 90 GHz. The measured input 1-dB compression point (IP1dB) is around -12 dBm in W-band.

  • 1
• Characterization of 2 μm band soliton optical comb based on silicon nitride microcavity

  CHENG Ru-Min, SUN Jia-Hao, WU Jia-Gui, GUO Deng-Ji, XU Jiao, YANG Jun-Bo, YAN Pei-Guang

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

  Abstract:

  The optical frequency combs(OFCs) generation of silicon nitride microcavities in the 2 μm band is investigated. Dispersion modulation of silicon nitride waveguides is carried out by geometrical design, appropriate bus waveguide dimensions are selected, and the thermal refraction noise of silicon nitride microcavities at different modulation frequencies is discussed from the thermal absorption theory. The nonlinear Schr?dinger equation is used as the basic model to study the evolution of the cavity under different dispersion effects. The numerical results show that silicon nitride is able to observe the hysteretic state transition of the system, i.e., the relaxation oscillation phenomenon during the transition of the system to the stable domain, more clearly in the 2 μm band, and at the same time, the cavity is able to transition to the steady state soliton faster under the action of the higher-order dispersion, which provides a scheme to study the respiratory soliton.

  • 1
• Physics model and experimental research on GaN-based lateral gate transistor terahertz detector

  KANG Ya-Ru, DONG Hui, LIU Jing, HUANG Zhen, LI Zhao-Feng, YAN Wei, WANG Xiao-Dong

  Abstract: (8) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  For the high-electron-mobility transistor(HEMT) terahertz detector with a side-gate structure, a physical model for DC transport and terahertz detection of the device was constructed. Using a self-alignment process, well-shaped and reliable contacts for the side-gate structure were successfully fabricated, effectively solving contact issues between the dual gates and the mesa. Ultimately, terahertz detectors with different gate widths(200 nm, 800 nm, and 1400 nm) of side-gate GaN/AlGaN HEMTs were obtained. DC tests revealed a clear linear relationship between the gate width of different devices and their threshold voltage, confirming the DC transport model of the side-gate HEMT terahertz detector. These results provide experimental verification and guidance for the theoretical model of the complete side-gate HEMT terahertz detector, offering significant support for the development of side-gate HEMT terahertz detectors.

  • 1
• Low Noise ROIC integrated with Correlated Double Sampling with Adjustable Interval for Hyperspectral Applications

  WuShuang, LIANG Qing-Hua, CHEN Hong-Lei, DING Rui-Jun

  Abstract: (5) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Low noise is a key requirement of readout integrated circuit (ROIC) in hyperspectral applications for its low radiation. Correlated double sampling (CDS) is commonly used to suppress noise. In this paper, CDS is improved by adjusting the time interval between the clamp and sample-and-hold (SH), which can filter low-frequency noise flexibly. A 640×512, 15μm pixel pitch ROIC is designed and fabricated in 180nm CMOS process. The input stage consists of low-noise capacitive trans-impedance amplifier (CTIA) and CDS with adjustable interval (AICDS). A timing generator is proposed to extend the CDS reset time from 0 to 270 clock cycles. By extending reset time to decrease the time interval, the noise electrons are significantly decreased from 39 e- to 18.3 e-. The SPECTRE simulation and the experimental results corroborate that the proposed structure AICDS can optimize noise performance of hyperspectral ROIC, thus can be widely used.

  • 1
• The scanning tunneling spectra of Hg0.72Cd0.28Te and the model interpretation

  Xiao Zheng-Qiong, Dai Hao-guang, Liu Xin-yang, Chen Ping-Ping, Zha Fang-Xing

  Abstract: (5) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The cross-sectional scanning tunneling microscopy (XSTM) technique was used to study the cleaved surface of Hg0.72Cd0.28Te grown by molecular beam epitaxy. Scanning tunnel spectroscopy (STS)’s measurements show that the width of zero current plateau (the apparent tunneling gap) of current-voltage (I/V) spectra is about 130% larger than the practical band gap of the material, implying the existence of obvious tip-induced band bending (TIBB) effect with the measurement. Based on the 3D TIBB model, the STS data can however be interpreted and the calculated I/V spectra are in good agreement with the measurement. Nevertheless, certain deviation appears for those I/V data which were acquired with a large imaging bias, e.g. 1.6 V. This is because the current TIBB model does not taken into account the transport mechanism of the material itself, for which the band-to-band tunneling, trap assisted tunneling etc. could be non-negligible factors for the tunneling.

  • 1
• Visible-NIR-II Dual-Channel Fluorescence Imaging System

  LIU Wen, NI Hu-Wei, QIAN Jun

  Abstract: (6) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  A dual-channel macroscopic imaging system has been developed based on optical methods, which can simultaneously capture the visible light and near-infrared second window (NIR-II) fluorescence. It could provide high-quality bright-field real-time images with the NIR-II fluorescence information, addressing the significant disparity issue between fluorescence and bright-field images in conventional NIR-II macroscopic imaging systems. In the experiment, the anti-scattering capability and imaging performance of NIR-II fluorescence signals of indocyanine green (ICG) were tested using different thicknesses of adipose tissues in the band of 1100-1700 nm and 1300-1700 nm respectively. Subsequently, the dual-channel macroscopic imaging system was used to obtain lymph node images of mouse and rat models, simulating the lymph node resection surgery and mimicking the process of abdominal lymph node clearance. Finally, different thicknesses of biological adipose tissues were added to the rat model to simulate the presence of adipose tissues covering the lymph nodes during actual surgery, and the penetration capability of the dual-channel system was observed. The visible and near-infrared second window dual-channel fluorescence imaging system provided the intuitive visual information to the operator, reducing surgery time and improving the patient prognosis, and held great potential for application in clinical surgical navigation.

  • 1
• Metal microstrip line defect detection of chip based on THzTDR technology

  xuzhen, XU De-Gang, LIU Long-Hai, LI Ji-Ning, ZHANG Jia-Xin, WANG Tan, REN Xiang, QIAO Xiu-Ming, JIANG Chen

  Abstract: (11) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The current main detection methods for packaging chip defects with small size, dense wiring, and high integration have drawbacks such as low accuracy and long cycle time. To compensate for the shortcomings of traditional detection methods, this study combines terahertz technology with time-domain reflection technology to explore the feasibility of detecting metal wire defects on chips. Firstly, different proportions of convex defects and concave defects were processed on metal microstrip lines of different widths to simulate incomplete opening/short circuits of metal wires in integrated chips. The time-domain reflection signals were collected using a terahertz time-domain reflectometer. Then, qualitative analysis was conducted on different defect degrees and types based on the corresponding time of time-domain reflection pulses, and the defect positions of the metal wires on the chip were accurately calculated. Finally, the finite element analysis method was used to simulate and analyze the metal wires with defects on the silicon substrate, which showed perfect consistency with the experimental results. This research shows that the combined terahertz technology with time-domain reflection technology can achieve the diagnosis and detection of metal wire defects on chips, providing an empirical reference for defect detection in integrated chips.

  • 1
• Improved liquid phase epitaxy method for in-situ growth of HgCdTe with positive composition gradient

  HUO Qin, HAN Hong-Qiang, ZHANG Cheng, JIAO Cui-Ling, WANG Reng, MAO Cheng-Ming, LU Ye, CHEN Xin-Tian, QIAO Hui, LI Xiang-Yang

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

  Abstract:

  The influence of growth conditions of liquid phase epitaxy on the composition gradient of HgCdTe was studied, and the growth model of liquid phase epitaxy of HgCdTe was established. HgCdTe with positive composition gradient was grown by slider liquid phase epitaxy by changing the mercury loss rate. The positive composition gradient structure of HgCdTe grown under the growth condition of specific mercury loss was confirmed by corrosion thinning spectrum and secondary ion mass spectrometry (SIMS). The experimental results show that the HgCdTe with positive composition gradient had the similar surface morphology and infrared transmission spectrum curve to the traditional HgCdTe with negative composition gradient; and it had high crystal quality,? with a full width at half maximum (FWHM) of X-ray diffraction（XRD）double-crystal rocking curve of 28.8 arcsec.

  • 1
• The research progress of millimeter-wave power applications

  LU Dun, FU Wen-Jie, MIKHAIL Glyavin, TANG Xiang-Wei, HU Min, LIU Sheng-Gang

  Abstract: (5) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In general, all known applications of high power microwaves directly use energy to interact with matter. In recent years, with the development of powerful millimeter-wave radiation sources, microwave technology has gradually drifted into the millimeter-wave frequency band. Due to the wavelength of radiation, millimeter waves have a number of unique characteristics, which allows both the active development of existing and the creation of new technologies that require high power or radiation energy. This article provides an overview of research work on the application of millimeter waves to solve problems in physics, materials science, biomedicine and others, including heating and diagnostics of thermonuclear plasma, processing and analysis of materials, biological effects, etc. The main difficulties arising in the implementation of the described tasks are presented, as well as future development is outlined.

  • 1
• Gradient-aware channel attention network for infrared small target image denoising before detection

  LIN Zai-Ping, LUO Yi-Hang, LI Bo-Yang, WU Tian-Hao, LING Qiang, XIAO Chao, LIU Ting, WU Jing

  Abstract: (8) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Infrared small target denoising is widely used in military and civilian fields. Existing deep learning-based methods are specially designed for optical images, which easily overall smooths the informative image details and thus loses the response of small target. To both denoise and maintain informative image details, this paper proposed a gradient-aware channel attention network (GCAN) for infrared small target image denoising before detection. Specifically, we first use a encoder-decoder network to remove the additive noise of the infrared images. Then, a gradient-aware channel attention module is designed to adaptively enhance the informative high-gradient image channel. The informative target region with high-gradient can be maintained in this way. After that, we develop a large dataset with 3981 noisy infrared images. Experimental results show that our proposed GCAN can both effectively remove the additive noise and maintain the informative target region. Additional experiments of infrared small targets detection further verify the effectiveness of our method. Our dataset and source-code will be available at https://github.com/yihang455/GCAN soon.

  • 1
• 1280×1024 dual-color mid-wavelength infrared InAs/GaSb superlattice focal plane arrays

  BAI Zhi-zhong

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

  Abstract:

  In this paper, we report research results of 1280×1024 dual-color mid-wavelength infrared InAs/GaSb superlattice focal plane arrays. The detector structure is PN-NP epitaxial multilayer and the signal is read out by sequential mode. The superlattice structure was grown on GaSb substrate using molecular beam epitaxy (MBE) technology. The respective structure of each absorption region are Mid-Wavelength 1(MW1): 6ML ( InAs) /7ML ( GaSb) and Mid-Wavelength 2 (MW2) : 9ML ( InAs) /7ML ( GaSb). The pixel center distance of the detector is 12μm. At 80 K measurement, the detector has spectral response wavelength of 3-4μm and 3.8-5.2μm respectively; The MW1 detector has a peak detectivity of 6.32×10₁₁^cmHz_1/2^W_-1^; The MW2 detector has a peak detectivity of 2.84×10₁₁^cmHz_1/2^W_-1^.Infrared images of both wavebands have been taken using infrared imaging test by adjusting devices voltage bias. Its the first time 1280 × 1024 InAs/GaSb Type II superlattice mid-wave length two-color infrared focal plane detector has been reported in China.

  • 1
• High-performance MOCVD-SiNx/AlN/GaN MIS-HEMTs with Low Noise and High Linearity for Millimeter Waves

  YUAN Jing, JING Guan-Jun, WANG Jian-Chao, WANG Liu, GAO Run-Hua, ZHANG Yi-Chuan, YAO Yi-Xu, WEI Ke, LI Yan-Kui, CHEN Xiao-Juan

  Abstract: (17) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In this paper, we demonstrated SiNx/AlN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) with low noise and high linearity, by in-situ growth of SiNx gate dielectrics on ultra-thin barrier AlN/GaN heterostructure. Deep-level transient spectroscopy (DLTS) shows a traps-level depth of 0.236 eV, a capture cross-section of 3.06×10-19 ^cm-², and an extracted interface state density of 1010 ^{to 10}12 ^cm-2^eV-1^; comfirming the efficiency of the grown SiNx in reducing the interface state. The devices exhibit excellent DC, small signal, and power performance, with a maximum saturation output current (Idmax) of 2.2 A/mm at the gate voltage (Vgs) of 2V and the gate length of 0.15 μm, a maximum current cutoff frequency (fT) of 65 GHz, a maximum power cutoff frequency (fMAX) of 123 GHz, a minimum noise figure (NFmin) of the device of 1.07 dB and the gain of 9.93 dB at 40 GHz. The two-tone measurements at the Vds of 6V, yield a third-order intermodulation output power (OIP3) of 32.6 dBm, and OIP3/Pdc of 11.2 dB. Benefited from the high-quality SiNx/AlN interface, the MIS-HEMTs exhibited excellently low noise and high linearity, revealing its potential in applications of millimeter waves.

  • 1
• Extracting the effective mass of fewer layers 2D h-BN nanosheets using the Fowler Nordheim tunneling model

  Qin Jia-Yi, Luo Man, Cheng Tian-Tian, Meng Yu-Xin, Zu Yuan-Ze, Wang Xin, Yu Chen-Hui

  Abstract: (29) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Hexagonal boron nitride (h-BN) finds widespread application, including gate dielectrics, passivation layers, and tunneling layers, owing to its outstanding properties. The current studies on the fundamental physical properties of these ultrathin h-BN films and the electron tunneling effect among them are inadequate. In this work, the effective mass in h-BN was successfully determined through a combined approach of experimental and theoretical research methods by fitting the current-voltage curves of metal/insulator/metal structures. It was observed that within a range of 4~22 layers, the effective mass of h-BN exhibits a monotonic decrease with an increase in the number of layers. Precisely ascertain the physical parameters of the Fowler-Nordheim tunneling model in the context of electron tunneling in h-BN by utilizing the extracted effective mass. Additionally, the impact of fixed charges at the metal/h-BN interface and various metal electrode types on Fowler-Nordheim tunneling within this structure was investigated utilizing this physical parameter in Sentaurus TCAD software. This work is informative and instructive in promoting applications in the fields of h-BN related infrared physics and technology.

  • 1
• Study on the multifunctional sequential structure film of perspective/shading/temperature control/infrared stealth

  Wang Long, Wang Liu-Ying, Liu Gu, Ge Chao-Qun, Wang Bin, Xu Ke-Jun, Wang Wen-Hao, Hu Ling-Jie

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

  Abstract:

  To solve the spectral demand and material design conflicts of multifunctional coupling and integration of optical materials, a collaborative design method based on [TiAlN/Ag]2/TiAlN sequential structure film for visible transmission induction and infrared radiation suppression is proposed, interpreting the new principles and mechanisms of multifunctional coupling of sequential structure film materials. Meanwhile, its optical compatibility performance is characterized. It shows that the [TiAlN (thickness 30 nm)/Ag (thickness 15 nm)] 2/TiAlN (thickness 30 nm) sequential composite film has the optical characteristics of band-pass selective transmission and mid-far infrared low radiation, which can better realize the multifunctional compatibility effects of perspective, shading, low radiation temperature control and infrared stealth, and can be used in the radiation temperature control and infrared stealth application fields of special glasses such as military vehicle and green buildings.

  • 1
• Dual-band multi-beam reconfigurable terahertz antenna based on graphene frequency selective surface

  JIN Zhao, Rong Yu, Yu Jing-Dong, Wu Fei

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

  Abstract:

  In this paper, a dual-band graphene-based frequency selective surface (GFSS) is investigated and the operating mechanism of this GFSS is analyzed. By adjusting the bias voltage to control the graphene chemical potential between 0eV and 0.5eV, the GFSS can achieve four working states: dual-band passband, high-pass low-impedance, low-pass high-impedance, and band-stop. Based on this GFSS, a hexagonal antenna cover loaded on a broadband omnidirectional monopole antenna is proposed, which can achieve independent 360° six-beam omnidirectional scanning at 1.08THz and 1.58THz dual bands. In addition, while increasing the directionality, the peak gains of the dual bands reach 7.44dBi and 6.67dBi, respectively. This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.

  • 1
• InAs/GaSb, Superlattice, Long Wavelength, Focal Plane Array

  BAI Zhi-Zhong

  Abstract: (18) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In this paper, we report research results of 12.5μm long-wavelength infrared InAs/GaSb superlattice focal plane arrays. The superlattice structure was grown on GaSb substrate using molecular beam epitaxy ( MBE) technology. The respective structure of absorption region is 15ML ( InAs) /7ML ( GaSb). The detector adopts PB-πBN double barrier structure to suppress the dark current. A long-wave focal plane detector with the size of 1024×1024 and the pixel center-to-center distance of 18×18μm was developed. The detector is packaged by a metal dewar, and a superlattice long-wavelength detector cryocooler assembly is formed by coupling with a refrigerator. At 60 K measurement, the detector has 50% cut-off wavelength of 12.5μm, The detector has a peak detectivity of 6.6×1010cmHz1/2W-1 , dead pixels rate of 1.05% and a noise equivalent temperature difference (NETD) is 21.2mK. Infrared images of this detector has been taken using infrared imaging test.

  • 1
• Investigation of Polarization Characteristics in Semiconductor Master Oscillator Power Amplifier

  Wang Hao-Miao, HE Yu-Wen, Li Yi, Hu Yao, Zhang Liang, Du Wei-Chuan, Gao Song-Xin, Tang Chun, Ma Xiao-Yu, Liu Su-Ping

  Abstract: (11) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  To improve of polarization of master oscillator power amplifier (MOPA), the factors which have impact on the polarization characteristics of ridge and tapered waveguides are studied. The optical confinement factor of TE-mode in ridge waveguide is enlarged by 1.35 μm deep etching, whereas the TE optical gain in tapered amplifier is improved through on-chip metal stress regulation. Combining the methods above, the degree of polarization (DOP) of two section are prominently enhanced in addition to reduced polarization angle difference. Finally, a 90% DOP of the MOPA has been achieved by standard process fabrication.

  • 1
• Study of infrared radiation suppression on solid surfaces by sprayed water film

  YANG Bin, LIU Zhi-Ling, HAN Lei, LI Zhi-Wei, WANG Zhen, AN Yi-Feng, HUANG Zhi-Feng

  Abstract: (16) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  To investigate the mechanism of infrared radiation suppression on solid surfaces by spraying water film and to establish an accurate calculation method for infrared radiation, theoretical and experimental research was conducted to study the influence of water film on the infrared radiation of solid surfaces. The results showed that in the 8~12 ?m wavelength range, the infrared radiation characteristics of a solid surface covered with a water film (with a thickness greater than 100 ?m) mainly relied on the infrared radiation emitted by the water film. An infrared radiation transfer model was developed to encompass solid surfaces covered with water film, and the accuracy of commonly used calculation methods in the literature was analyzed. The error in calculating infrared radiation using the free surface temperature of the water film was less than 0.3%, while the maximum error in calculating infrared radiation using the temperature of the solid surface was 8.32%.

  • 1
• Design and fabrication of an ultra-broadband dichroic beam-splitter with low polarization

  Yu Tianyan, Qin Yang, Jiang Lin, Liu Dingquan

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

  Abstract:

  This paper describes the design and fabrication of one kind of dichroic beam-splitter that operates in an ultra-broadband spectral range from visible to longwave infrared regions simultaneously. The use of metal-dielectric coatings makes it implement structures that transmit the visible/near infrared radiation from 0.4 to 1.05mm and reflect infrared radiation from 1.36 to 13mm. At the same time, the structures are designed to obtain a low linear polarization sensitivity (Lps) in the visible/near infrared region. The transmission of visible/near infrared region is more than 85% and the average reflection of infrared region is more than 90%. The LPS of the region 0.4~1.05mm is less than 4%.

  • 1
• Development of a homodyne mixing system for performance characterization of terahertz superconducting KIDs

  zhangjiawen, Jing Jun-Da, SHI Sheng-Cai, Li Jing, Lv Wei-Tao, Li Zhi, Zhi Qiang, Peng Zhaohang

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

  Abstract:

  The homodyne mixing system is used to characterizing the performance of terahertz superconducting kinetic inductance detectors (KIDs). However, homodyne mixing systems still have issues such as mixer imbalance, measurement system integration, and interference signals. The author designed a new single channel homodyne mixing hardware system and software algorithms to achieve integration of the measurement system, calibration of IQ-mixer imbalance, and performance characterization of KID; Furthermore, noise measurement of KIDs in VNA (vector network analyzer) CW mode is achieved; Finally, the method of hardware circuit design by dual channel homodyne mixing system based on autocorrelation algorithm effectively suppresses interference signals. It is worth noting that these research results are applied to characterize the performance of KIDs, which is important in the design of KIDs arrays.

  • 1
• Characterization of visible-mid-infrared supercontinuum spectrum based on sandwiched silicon nitride waveguide

  SUN Jia-Hao, CHENG Ru-Min, GUO Kai, YIN Jin-De, QING Du-An, LI Ling, YANG Pei-Guang

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

  Abstract:

  This paper introduces a low-thickness sandwich waveguide structure comprising silicon nitride (Si3N4)-sapphire (Al2O3)-silicon nitride layers. By exploiting its dispersion wave (DW) radiation effect and mid-infrared phase matching condition, combined with the waveguide pulse transmission model, this study examines the impact of different physical sizes of the sandwich waveguide on the phase matching point and spectral broadening. Through numerical simulation, a supercontinuum spectrum ranging from 0.5 to 4 μm is generated, producing a farther mid-infrared dispersion wave at a -40 dB level. Moreover, this model provides an in-depth mechanism for nonlinear waveguide pulse transmission. Theoretical analysis reveals that modifying the physical size of the silicon nitride and sapphire interlayer and altering the phase-matching conditions can regulate the position of the dispersion wave across a broader wavelength range.

  • 1
• Non-destructive thickness measurement with micron level accuracy based on a 4.3-THz quantum-cascade laser

  LI Hong-Yi, TAN Zhi-Yong, WAN Wen-Jian, CAO Jun-Cheng

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

  Abstract:

  A homodyne detection system to acquire the thickness of silicon wafers is constructed and described. By harnessing the relationship between the transmission phase change of a 4.3-THz light beam and the incident angle controlled by a mechanical rotating stage, the thickness value of sample can be precisely deduced using the standard residual error method. The results indicate that the fitted thickness of the sample differs by only 2.5~3 μm from more accurate results measured by optical microscopes, achieving terahertz non-destructive thickness measurement with micron level accuracy. The experiment validates the effectiveness of terahertz quantum-cascade laser in non-contact and nondestructive measurement.

  • 1
• Terahertz spectroscopy and weak interactional investigation of cinnamic acid derivatives

  ZHENG Zhuan-Ping, ZHAO Shuai-Yu, LIU Yu-Hang, JIANG Jie-Wei

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

  Abstract:

  The THz absorption spectra of three cinnamic acid derivatives (CADs): p-coumaric acid (PCA), trans o-coumaric acid (OCA) and 4-fluorocinnamic acid (4-FCA) were measured in the range of 0.5-3.5 THz using terahertz time-domain spectroscopy (THz-TDS). Density functional theory (DF T) was employed along with the vibrational mode automatic relevance determination (VMARD) method to interpret the origins of the THz absorption peaks. In addition, the types of weak intermolecular forces in the molecular systems were analyzed by using the molecular force field energy decomposition analysis (EDA-FF). The atomic coloring diagram was drawn by Visual Molecular Dynamics (VMD) for visual analysis. Then the contribution types and strengths of its atoms to the weak interactional forces in the molecular system were studied. These investigation indicate that the combination of THz-TDS, DFT, VMARD, and EDA-FF methods not only can effectively distinguish organic molecules with structural isomers or structural similarities but also can provide valuable reference data for uncovering their biochemical functionalities.

  • 1
• Terahertz study on the porosity of porous traditional Chinese medicine tablets by effective medium models

  LI Xu, ZHANG Meng-Yuan, ZHAO Wen-Yue, ZUO Jian, ZHU Wei-Feng, LI Zhe, SHI Yu-Lei, ZHANG Cun-Lin

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

  Abstract:

  Generally, the porosity of traditional Chinese medicine is measured by the destructive method of density measurement, but there is a lack of non-destructive quantification methods. As one important non-destructive method, terahertz radiation has been used to non-destructively extract the drugs" time-domain and frequency-domain optical information. For direct compression traditional Chinese medicine tablets, the effective refractive index of various tablets was obtained by different methods of terahertz time-domain signal processing and frequency-domain signal processing. It was found that the effective refractive indices with either signal processing method show a good linear relationship with the porosities of the tablets. The porosity of Puerariae Lobatae Radix tablets was extracted and modeled by linear regression based on four effective medium theory models. The porosity regression model based on the effective refractive index by time-domain signal processing shows better performance on the model interpretation and cross-validation accuracy, with the best model of the Bruggeman model (RPD=11.3325). It provides support for the process optimization of porous powder preparation of traditional Chinese medicine.

  • 1
• Ultrasensitive and Broad-Spectrum Photodetectors Based on InSe/MoTe₂ Heterostructure

  XING Yan-Hui, HE Wen-Xin, HAN Zi-Shuo, GUAN Bao-Lu, MA Hai-Xin, MA Xiao-Hui, HAN Jun, SHI Wen-Hua, ZHANG Bao-Shun, LV Wei-Ming, ZENG Zhong-Ming

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

  Abstract:

  The grating effect based on the vertical structure of a two-dimensional material allows high-sensitivity and broad-spectrum photodetector. In this paper, a high-sensitivity photodetector based on the vertical heterostructure of indium selenide (InSe)/molybdenum ditelluride (MoTe2) is reported, which exhibits excellent broad-spectrum detection capability from 365 to 965 nm. The top layer of InSe is used as the grating layer to regulate the channel current, and MoTe2 is used as the transmission layer. By combining the advantages of the two materials, the photodetector has a fast response time of 21.6 ms and achieves a maximum detectivity of 1.05 × 10^13 Jones under 365 nm laser irradiation. Under the illumination of 965nm, the detectivity still achieves the order of 10^9 Jones. In addition, The InSe/MoTe2 heterostructure exhibits an external quantum efficiency of 1.03 × 10&5%, which demonstrates a strong photoelectric conversion capability.

  • 1
• A microscopic image enhancement method for cell experiments in space

  Li Yuan-Yuan, Yuan Yong-Chun, Ruan Li-Hua, Zhao Qing-Qing, Zhang Tao

  Abstract: (51) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  High image quality is crucial for cell experiments in space, as it requires the ability of remotely monitoring to grasp the progress and direction of experiments. However, due to space limitations and environmental factors, imaging equipment is strongly constrained in some performance, which directly affects the imaging quality and observation of cultivated targets. Moreover, experimental analysis on the ground requires tasks such as feature extraction and cell counting, but uneven lighting can seriously affect computer processing. Therefore, a method called STAR-ADF is proposed, and experiments show that the method can effectively remove noise, equalize illumination, and increase the enhancement evaluation index by 12.5% compared with the original figure, and has certain robustness.

  • 1
• Study on the relationship between polarization and transverse modes of narrow ridge waveguide semiconductor lasers

  SONG Liang, HE Yu-Wen, WANG Hao-Miao, ZHOU Kun, DU Wei-Chuan, LI Yi, HE Lin-An, HU Yao, ZHANG Liang, GAO Ping-Kuang, WANG Xin-Yang, GAO Song-Xin, TANG Chun

  Abstract: (15) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  Based on the effective refractive index method, a numerical calculation model of the narrow ridge waveguide was established. The relationship between the polarization characteristics and the transverse mode of the InGaAs quantum well narrow ridge waveguide semiconductor laser was studied experimentally. According to theoretical calculations, the effective refractive index difference of the TM-like mode in the ridge waveguide is larger in the direction of the slow axis. The confinement factor of the TM-like mode is larger than that of the TE-like mode, and the slow-axis high-order mode is more likely to appear. As the height of the ridge waveguide increases, the fast-axis high-order modes are truncated, and the confinement factor of the TE00-like mode gradually increases to be similar to that of the TM00-like mode. The slow-axis high-order mode is suppressed due to its large scattering loss, resulting in a theoretically high, highly polarized beam quality laser output. In terms of experiments, a narrow ridge waveguide semiconductor laser with a high degree of polarization and a fundamental transverse mode was fabricated by using the gain polarization characteristics of quantum well materials and by designing the height and width of the ridge.

  • 1
• Study on I Layer of APD P-I-N HgCdTe

  Shen Chuan, Zhang Jing, Yang Liao, Guo Huijun, Xie Hao, Zhou Meihua, Chen Lu, He Li

  Abstract: (20) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  In this paper, the crystal quality of materials in key avalanche region of Mercury Cadmium telluride (HgCdTe) avalanche photodiode detector(APD) with medium wave PIN structure is studied. By simulating the entire process of the PIN APD device on the experimental material, and using differential Hall and differential minority lifetime test to characterize the material, the real crystal quality of the key avalanche area was evaluated. It is found that the crystal quality of the avalanche region under the optimized process is good, and its SRH lifetime can reach 20.7μs, which can reach the SRH lifetime of the primary material. This meets the development requirements of high quality medium-wave mercury cadmium telluride avalanche devices. At the same time, based on the obtained SRH lifetime in the avalanche region, we conducted corresponding two-dimensional numerical simulations on HgCdTe APD structural devices to obtain the theoretically optimal dark current density of 8.7×10-1⁰A/cm2^.

  • 1
• Difference and parameter analysis of LST inversion based on Landsat data

  Wan Ji-Kang, Shen Zhe-Hui, Li Shan

  Abstract: (40) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The correct use of the product is possible only when the land surface temperature (LST) data is calculated by an accurate and reliable inversion algorithm. In this paper, we compare the inversion results of five commonly used LST inversion algorithms based on Landsat-8, Landsat-9 data, and weather station data. The inversion results and parameter sensitivity analysis of different algorithms are tested. The results show that the algorithm of Landsat-8 can also be applied to Landsat-9 data. The inversion results of the Radiative Transfer Equation (RTE) and Single Channel (SC) algorithms calculated based on land surface emissivity (LSE) are in good agreement with the ground measured. The inversion results of the SC algorithm based on atmospheric water vapor inversion and the Split Window (SW) algorithm based on atmospheric water vapor inversion are higher than the measured temperature. The inversion accuracy of the Mono Window (MW) algorithm based on average temperature parameters is not ideal. In addition, the consistency of the inversion temperature of the two data on different ground objects was compared. Our study can provide a reference for land surface temperature inversion based on Landsat-9 data.

  • 1
• Study on the optical properties of VO2 thin films under varied temperatures and the protection performance against 1550nm laser

  DUAN Jia-Xin, JIANG Lin, ZHENG Guo-Bin, HUANG Jing-Guo, Gao Yan-Qing, ZHOU Wei, HUANG Zhi-Ming

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

  Abstract:

  Vanadium dioxide materials, which show semiconductor-metal phase transition, can be used for protection of photoelectric detectors against laser blinding weapons. The structure, morphology and optical properties of vanadium dioxide thin films prepared by radio frequency magnetron sputtering at different temperatures were reported. The visible to infrared ellipsometric parameters of vanadium dioxide film at "20~100 ℃" were measured by using an ellipsometer. The optical properties of vanadium dioxide films before phase transition were obtained by Gaussian and Lorentz model, and the optical properties after phase transition were obtained by adding a Drude model. The refractive index and extinction coefficient between 300 nm and 1800 nm were obtained. The transmittance spectrum of 1550 nm infrared laser at varied power densities shows that the threshold power of phase transformation is about 12 W/cm2, where the transmittance decreases sharply from 51% to 17%.

  • 1
• High-performance Spectro-Polarimetric Filter by integrating Subwavelength Gratings with Fabry-Perot filter

  ZHU Yuan-Yu, GUAN Xue-Yu, YU Pei-Qi, LIU Qing-Quan, JIA Qi-Xiang, WU Jie, LI Chen-Lu, LI Zhi-Feng, WANG Shao-Wei

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

  Abstract:

  Spectral polarization imaging technology is a novel optical imaging technique that not only enhances the amount of information acquired from targets, but also reduces background noise, which can capture target details and detect disguised targets. This paper presents a spectro-polarimetric device by integrating subwavelength gratings with Fabry-Perot (F-P) filter, which can obtain ultra-high spectral resolution and polarization extinction ratio with high control flexibly on both spectrum and polarization. A pectro-polarimetric filter has been designed to obtain 4 spectral channels of stokes parameters simultaneously. Simulation results show that it has a spectral resolution (SR, ) of 217 and polarization extinction ratio (PER) of . The polarization extinction ratio of subwavelength grating is measured to be over 500 PER with 90% transmission efficiency. The spectral resolution of all-dielectric F-P filter is measured to be30 with 60% transmission efficiency in the long wave infrared band. The design method is universal and can be used in a wide range of wavelength bands such as visible, infrared, and even terahertz. It has great potential applications in fields such as micro-polarization spectrometers and full-stokes polarization detection, benefiting from these advantages.

  • 1
• Spectrum selection and performance analysis for ship detection

  zhanglei, qiaokai, huangshisheng

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

  Abstract:

  The detection of ships and other sea targets is of great significance to sea surface management, national defense security, search and rescue and other fields. Space-borne infrared remote sensing has a wide coverage and a short atmospheric path, which is an effective means to achieve wide-area detection of ship targets. Affected by the diurnal cycle of the solar zenith angle, the temperature difference between the ship and the sea surface changes periodically, resulting in a thermal crossover period twice a day in the ship detection scene on the sea surface. In this paper, taking the mid-latitude summer and winter sea surface environment as an example, the 24-hour infrared radiation characteristics of the sea surface ship detection scene are established, and a multi-spectrum optimal combination scheme is proposed, which is realized by the detection of dual detection spectrum bands of 3.50 μm~4.10μm and 10.25μm~10.75μm Day and night continuous observation with signal-to-noise ratio better than 16.52(summer) and 17.64(winter). The proposed dual-spectrum detection method provides technical support for the application of wide-area all-time sea surface target detection.

  • 1
• A metamaterial absorber with electrically and thermally tunable absorption frequency and absorptivity

  hubaojing, yangli

  Abstract: (18) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  A dual-tunable "perfect" metamaterial absorber composed of a "Tian-zi"-shaped Dirac semimetal (BDS) resonator and strontium titanate (STO) is proposed in this work and systematically studied by performing numerical simulations. From the acquired results, it is demonstrated that the absorber can achieve 99% absorption rate at 2.6131 THz when the BDS Fermi energy is 40 meV and the STO temperature is 400 K. Moreover, both dynamic dual-tuning of the absorption frequency and absorption rate of the absorber can be successfully achieved by varying the BDS Fermi energy level and the STO temperature. Additionally, the absorber's performance is theoretically analyzed using both coupled mode theory (CMT) and the equivalent circuit model (ECM). Finally, the changes in the absorber's absorption spectrum are further discussed when each parameter of the model is modified, providing thus a solid theoretical basis for the design of dual-tunable filters and absorbers.

  • 1
• A new method for retrieving the near-space temperature profile based on the 1.27 μm O2 airglow

  WANG Dao-Qi, WANG Hou-Mao, HU Xiang-Rui, HE Wei-Wei, LI Fa-Quan, WU Kui-Jun

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

  Abstract:

  The high radiation intensity and weak self-absorption effect of the O2(a1?g) airglow in the 1.27 μm band make it an ideal target source for retrieval of the atmospheric temperature in the near-space. Based on the theory of O2 airglow spectral and the "onion-peeling" algorithm, the near-infrared limb-viewing data of the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) were successfully used to retrieve the atmospheric temperature profiles in the range of 50-100 km. Comparison with SABER, ACE-FTS and LIDAR observations shows that the temperature measurement error better than ±10 K in the tangential altitude of 55-85 km. However, in the space region below 55 km and above 85 km, the temperature retrieval results show significance biased due to the influences of self-absorption effects, atmospheric scattering, and spectral contamination from OH airglow.

  • 1
• Uncooled InAsSb-based high-speed mid-wave infrared barrier detector

  JIA Chun-Yang, DENG Gong-Rong, ZHAO Peng, ZHU Zhi-Zhen, ZHAO Jun, ZHANG Yi-Yun

  Abstract: (49) HTML (0) PDF (0.00 ByteKB) (0)

  Abstract:

  The demand for high-speed response mid-wave infrared (MWIR) photodetectors (PDs) is gradually increasing in emerging fields such as free-space optical communication and frequency comb spectroscopy. The XBnn barrier infrared photodetectors greatly suppress shot noise originated from bulk dark current. InAsSb/AlAsSb/AlSb-based nBn and pBn barrier MWIR PDs were grown on GaSb substrates using molecular beam epitaxy (MBE). The GSG PDs were fabricated to realize the radio frequency (RF) response testing. X-ray diffraction (XRD) and atomic force microscopy (AFM) results indicate that both epitaxial structures exhibit good crystal quality. The 90 μm diameter pBn PDs exhibit a lower dark current density of 0.145 A/cm2 compared to the nBn PDs operating at room temperature (RT) and reverse bias of 400 mV, which indicates the uncooled barrier PDs perform with low noise. According to R0A results of PDs with different mesa diameter, the pBn PDs exhibit surface resistivity of approximately 1.7×104 ^Ω.cm, higher than 3.1×103 ^Ω.cm of nBn PDs. The contributions of the R0A volume terms for pBn and nBn were 16.60 Ω.cm2 and 5.27 Ω.cm2, respectively. Capacitance tests reveal that the pBn PDs, operating at zero bias, show a fully depleted barrier layer and partially depleted absorption region, while the nBn absorption region also exhibit partial depletion. RF response characterization demonstrate that the 90 μm diameter pBn PDs achieve 3dB bandwidth of 2.62 GHz at room temperature and under 3V reverse bias, which represents a 29.7% improvement over the corresponding nBn PDs, which only achieve 3dB bandwidth of 2.02 GHz. This signifies a preliminary achievement of uncooled barrier MWIR PDs capable of fast detection.

  • 1

Volume 42,2023 Issue 6

• 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: (1505) HTML (139) PDF (262.82 KKB)(50496)

  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: (7627) HTML (465) PDF (411.06 KKB)(20476)

  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: (10451) HTML (415) PDF (221.64 KKB)(14153)

  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: (7233) HTML (402) PDF (271.63 KKB)(13604)

  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: (11176) HTML (387) PDF (808.83 KKB)(11154)

  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.

• HYPERSPECTRAL REMOTE SENSING IMAGE CLASSIFICATION BASED ON SUPPORT VECTOR MACHINE

  TAN Kun, DU Pei-Jun

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

  Abstract: (2868) HTML (936) PDF (735.00 KKB)(10642)

  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.

Image Processing and Software Simulation

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

  ZHOU Yue, MAO Xiao-Nan

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

  Abstract: (11181) HTML (439) PDF (750.21 KKB)(10445)

  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.

• 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: (11644) HTML (435) PDF (1.12 MKB)(10056)

  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: (1294) HTML (99) PDF (380.01 KKB)(9923)

  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.

• TWO-FREQUENCY SCATTERING CROSS SECTION AND PULSE BROADINGENING FOR THE FRACTAL SEA SURFACE WITH PULSE BEAM INCIDENCE

  GUO Li Xin 1) KIM Che Young 2)

  2003,22(2):132-136, DOI:

  Abstract: (899) HTML (132) PDF (396.69 KKB)(9857)

  Abstract:

  根据粗糙面基尔霍夫小斜率近似研究了脉冲波入射时实际海谱分布的一维分形海面的电磁散射。分析了毫米波入射时不同分维、入射角和入射中心频率下双频散射截面的散射角分布。结果表明分形海面的双频散射截面在镜反射方向有最大的相关带宽，随着海面分维的减小、入射中心频率和入射角的增加，该相关带宽是增大的。对于入射功率为δ函数时的散射波功率是一个具有一定脉冲展宽的散射脉冲，且脉冲展宽与相关带宽成反比关系。

• 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: (7720) HTML (181) PDF (466.11 KKB)(8761)

  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.

Remote Sensing Technology and Application

• A method for fire detection using Landsat 8 data

  HE Yang, YANG Jin, MA Yong, LIU Jian-Bo, CHEN Fu, LI Xin-Peng, YANG Yi-Fei

  2016,35(5):600-609, DOI: 10.11972/j.issn.1001-9014.2016.05.015

  Abstract: (3359) HTML (239) PDF (5.05 MKB)(8536)

  Abstract:

  Traditional fire detection methods use the high temperature emission characteristics in mid or thermal infrared bands of the MODIS or AVHRR data to extract burning area. It is very hard for these methods to identify small fire regions such as sub-pixel due to the limitation of spatial resolution. Recently researchers have found that shortwave infrared (SWIR) data can also be used to identify and detect high temperature targets. Compared with the thermal infrared data, SWIR has a big discrimination against different features with different temperature. Thus it can identify accurately the location of high temperature targets. In this paper, we acquired fire point products by using Landsat-8 OLI data which has spatial resolution up to 30 m. The main procedure includes two steps. The improved Normalized Burning Ratio Short-wave(NBRS) is calculated at first to adaptively acquire suspected fire points based on the spectral characteristics of fire points in the near infrared and shortwave infrared. Then most false positive points are excluded based on the relationship between peak value in shortwave infrared band of fire points. This algorithm is capable of detecting the burning area around 10% in one pixel. With the premise of avoiding the interference of cloud and constructions, it can also keep a nearly 90% accuracy and low missing rate around 10%.

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: (2472) HTML (131) PDF (1.09 MKB)(8466)

  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.

Infrared Materials and Devices

• Graphene oxide: progress in preparation, reduction and application

  ZHANG Qian, TANG Li-Bin, LI Ru-Jie, XIANG Jin-Zhong, HUANG Qiang, LIU Shu-Ping

  2019,38(1):79-90, DOI: 10.11972/j.issn.1001-9014.2019.01.014

  Abstract: (2763) HTML (215) PDF (4.42 MKB)(8352)

  Abstract:

  With the rapid development of graphene industry, graphene oxide has attracted much attention as an important intermediate product for the preparation of graphene. Due to its excellent physical and chemical properties, it has been widely used in multitudinous fields. Various structural models, preparation methods, properties and related applications, as well as the reduction of graphene oxide are summarized. The choice of oxidants and reduction agents were found to be important in the reaction. The basic selective principles are discussed after comparing various methods. Finally, it is pointed out that there are still some problems to be solved in the preparation and reduction of graphene oxide. The prospect of graphene oxide on its development and influence will also be evaluated.

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: (3500) HTML (195) PDF (1.64 MKB)(8324)

  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.

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: (2457) HTML (62) PDF (571.44 KKB)(8147)

  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

• 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: (3280) HTML (165) PDF (3.92 MKB)(7961)

  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.

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: (5092) HTML (160) PDF (704.75 KKB)(7926)

  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: (1480) HTML (109) PDF (520.22 KKB)(7879)

  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: (1785) HTML (111) PDF (363.60 KKB)(7809)

  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．