In order to meet the urgent need of infrared search and track applications for accurate identification and positioning of infrared guidance aircraft,an active-detection mid-wave infrared search and track system(ADMWIR...In order to meet the urgent need of infrared search and track applications for accurate identification and positioning of infrared guidance aircraft,an active-detection mid-wave infrared search and track system(ADMWIRSTS)based on"cat-eye effect"was developed.The ADMWIRSTS mainly consists of both a light beam control subsystem and an infrared search and track subsystem.The light beam control subsystem uses an integrated opto-mechanical two-dimensional pointing mirror to realize the control function of the azimuth and pitch directions of the system,which can cover the whole airspace range of 360°×90°.The infrared search and track subsystem uses two mid-wave infrared cooled 640×512 focal plane detectors for co-aperture beam expanding,infrared and illumination laser beam combining,infrared search,and two-stage track opto-mechanical design.In this work,the system integration design and structural finite-element analysis were conducted,the search imaging and two-stage track imaging for external scenes were performed,and the active-detection technologies were experimentally verified in the laboratory.The experimental investigation results show that the system can realize the infrared search and track imaging,and the accurate identification and positioning of the mid-wave infrared guidance,or infrared detection system through the echo of the illumination laser.The aforementioned work has important technical significance and practical application value for the development of compactly-integrated high-precision infrared search and track,and laser suppression system,and has broad application prospects in the protection of equipment,assets and infrastructures.展开更多
Type-Ⅱsuperlattice(T2SL)materials are the key element for infrared(IR)detectors.However,it is well known that the characteristics of the detectors with the T2SL layer are greatly affected by the strain developed duri...Type-Ⅱsuperlattice(T2SL)materials are the key element for infrared(IR)detectors.However,it is well known that the characteristics of the detectors with the T2SL layer are greatly affected by the strain developed during the growth process,which determines the performance of IR detectors.Therefore,great efforts have been made to properly control the strain effect and develop relevant analysis methods to evaluate the strain-induced dark current characteristics.In this work,we report the strain-induced dark current characteristics in InAs/GaSb T2SL MWIR photodetector.The overall strain of InAs/GaSb T2SL layer was analyzed by both high-resolution X-ray diffraction(HRXRD)and the dark current measured from the absorber layer at the elevated temperatures(≥110 K),where the major leakage current component is originated from the reduced minority carrier lifetime in the absorber layer.Our findings indicate that minority carrier lifetime increases as the tensile strain on the InAs/GaSb T2SL is more compensated by the compressive strain through‘InSb-like’interface,which reduces the dark current density of the device.Specifically,tensile strain compensated devices exhibited the dark current density of less than 2×10^-5 A/cm^2 at 120 K,which is more than one order of magnitude lower value compared to that of the device without tensile strain relaxation.展开更多
The Advanced Geosynchronous Radiation Imager(AGRI)onboard China’s Fengyun(FY)-4 satellites,which provides observational data across various wavelengths from visible to infrared(IR),holds great potential for diverse a...The Advanced Geosynchronous Radiation Imager(AGRI)onboard China’s Fengyun(FY)-4 satellites,which provides observational data across various wavelengths from visible to infrared(IR),holds great potential for diverse applications.However,the FY-4A AGRI mid-wave IR(MWIR)band(3.75µm)is often contaminated by stray light in the midnight hours during the 1-2 months before and after the vernal or autumnal equinoxes.In this study,a U-Net-based deep learning model was employed to generate an expedient MWIR band from the FY-4A AGRI long-wave IR band.Validation using normal radiance measurements revealed that MWIR brightness temperatures generated by the deep learning model are very close to those observed by the FY-4A AGRI,with mean absolute error of 1.48 K,root mean square error of 2.39 K,and a correlation coefficient of 0.99.When applying the model to periods of stray light contamination,the brightness temperature anomalies found in the FY-4A AGRI MWIR band are effectively eliminated.The findings of this study could support various scientific applications that necessitate use of the MWIR band during midnight hours,such as identification of fog/low stratus cloud.展开更多
This work proposes a novel design for a narrowband filter operating in the mid-wave infrared(MWIR)spectrum.The filter is designed with a single layer of slab waveguide decorated with a layer of gold grating arrays.Thi...This work proposes a novel design for a narrowband filter operating in the mid-wave infrared(MWIR)spectrum.The filter is designed with a single layer of slab waveguide decorated with a layer of gold grating arrays.This design demonstrates superior narrowband transmission properties within the MWIR range,which can be explained in the framework of guided-mode resonance(GMR).Since MWIR spectral data is crucial for identifying the chemical fingerprint of man-made objects and natural materials,the GMR filters hold great potential in integration with commercial MWIR photodetectors and focal plane arrays(FPAs)and addressing the market’s demand for ultra-compact spectral detection solutions.Theoretical studies have investigated the influential parameters in the GMR filter design and provided the methods towards optimal filtering performance.The center wavelength of these transmission filters exhibits significant tunability,spanning from 3μm to 5μm across the MWIR spectrum,while the full width at half maximum(FWHM)exhibits remarkable variability,ranging from 5.7 nm to 101.0 nm,enabling the attainment of desired filter performance contingent upon judicious waveguide material selection and optimized structural design.This work forges a path toward integrating multifunctional capabilities into ultra-compact MWIR sensors.展开更多
基金Supported by the Fundamental Scientific Research Plan of China(JCKY2021130B033)。
文摘In order to meet the urgent need of infrared search and track applications for accurate identification and positioning of infrared guidance aircraft,an active-detection mid-wave infrared search and track system(ADMWIRSTS)based on"cat-eye effect"was developed.The ADMWIRSTS mainly consists of both a light beam control subsystem and an infrared search and track subsystem.The light beam control subsystem uses an integrated opto-mechanical two-dimensional pointing mirror to realize the control function of the azimuth and pitch directions of the system,which can cover the whole airspace range of 360°×90°.The infrared search and track subsystem uses two mid-wave infrared cooled 640×512 focal plane detectors for co-aperture beam expanding,infrared and illumination laser beam combining,infrared search,and two-stage track opto-mechanical design.In this work,the system integration design and structural finite-element analysis were conducted,the search imaging and two-stage track imaging for external scenes were performed,and the active-detection technologies were experimentally verified in the laboratory.The experimental investigation results show that the system can realize the infrared search and track imaging,and the accurate identification and positioning of the mid-wave infrared guidance,or infrared detection system through the echo of the illumination laser.The aforementioned work has important technical significance and practical application value for the development of compactly-integrated high-precision infrared search and track,and laser suppression system,and has broad application prospects in the protection of equipment,assets and infrastructures.
基金supported by the research fund of Chungnam National University
文摘Type-Ⅱsuperlattice(T2SL)materials are the key element for infrared(IR)detectors.However,it is well known that the characteristics of the detectors with the T2SL layer are greatly affected by the strain developed during the growth process,which determines the performance of IR detectors.Therefore,great efforts have been made to properly control the strain effect and develop relevant analysis methods to evaluate the strain-induced dark current characteristics.In this work,we report the strain-induced dark current characteristics in InAs/GaSb T2SL MWIR photodetector.The overall strain of InAs/GaSb T2SL layer was analyzed by both high-resolution X-ray diffraction(HRXRD)and the dark current measured from the absorber layer at the elevated temperatures(≥110 K),where the major leakage current component is originated from the reduced minority carrier lifetime in the absorber layer.Our findings indicate that minority carrier lifetime increases as the tensile strain on the InAs/GaSb T2SL is more compensated by the compressive strain through‘InSb-like’interface,which reduces the dark current density of the device.Specifically,tensile strain compensated devices exhibited the dark current density of less than 2×10^-5 A/cm^2 at 120 K,which is more than one order of magnitude lower value compared to that of the device without tensile strain relaxation.
基金Supported by the National Natural Science Foundation of China(42305177 and 42175006)Beijige Foundation(BJG202210)Open Research Program of the State Key Laboratory of Severe Weather(2023LASW-B16).
文摘The Advanced Geosynchronous Radiation Imager(AGRI)onboard China’s Fengyun(FY)-4 satellites,which provides observational data across various wavelengths from visible to infrared(IR),holds great potential for diverse applications.However,the FY-4A AGRI mid-wave IR(MWIR)band(3.75µm)is often contaminated by stray light in the midnight hours during the 1-2 months before and after the vernal or autumnal equinoxes.In this study,a U-Net-based deep learning model was employed to generate an expedient MWIR band from the FY-4A AGRI long-wave IR band.Validation using normal radiance measurements revealed that MWIR brightness temperatures generated by the deep learning model are very close to those observed by the FY-4A AGRI,with mean absolute error of 1.48 K,root mean square error of 2.39 K,and a correlation coefficient of 0.99.When applying the model to periods of stray light contamination,the brightness temperature anomalies found in the FY-4A AGRI MWIR band are effectively eliminated.The findings of this study could support various scientific applications that necessitate use of the MWIR band during midnight hours,such as identification of fog/low stratus cloud.
基金supported by the National Key Research and Development Program of China under Grant No.2019YFB2203400the National Natural Science Foundation of China under Grant No.61974014.
文摘This work proposes a novel design for a narrowband filter operating in the mid-wave infrared(MWIR)spectrum.The filter is designed with a single layer of slab waveguide decorated with a layer of gold grating arrays.This design demonstrates superior narrowband transmission properties within the MWIR range,which can be explained in the framework of guided-mode resonance(GMR).Since MWIR spectral data is crucial for identifying the chemical fingerprint of man-made objects and natural materials,the GMR filters hold great potential in integration with commercial MWIR photodetectors and focal plane arrays(FPAs)and addressing the market’s demand for ultra-compact spectral detection solutions.Theoretical studies have investigated the influential parameters in the GMR filter design and provided the methods towards optimal filtering performance.The center wavelength of these transmission filters exhibits significant tunability,spanning from 3μm to 5μm across the MWIR spectrum,while the full width at half maximum(FWHM)exhibits remarkable variability,ranging from 5.7 nm to 101.0 nm,enabling the attainment of desired filter performance contingent upon judicious waveguide material selection and optimized structural design.This work forges a path toward integrating multifunctional capabilities into ultra-compact MWIR sensors.
