Wang Fei, zhang yuan, Jiang Yuying, Ge Hongyi, Chen Xinyu, L. Li
The traditional moldy wheat identification and detection method require complex processing steps, which take a long time and have less feature extraction ability, resulting in poor moldy wheat identification and detection. In this paper, a F-C-BLS terahertz spectral image recognition method for moldy wheat is proposed based on broad learning system. The F-C-BLS moldy wheat classification and recognition model is constructed to enhance the image quality and improve the network feature extraction. Experimental results show that the classification accuracy of our F-C-BLS network is 5.11%, 5.27%, 3.89 and 4.06% higher than that of BLS, RF, CNN and RNN, respectively. Therefore, our algorithm can effectively provide a new and effective method for the early identification of wheat mold.
{"title":"Identification of moldy wheat in terahertz images based on broad learning system","authors":"Wang Fei, zhang yuan, Jiang Yuying, Ge Hongyi, Chen Xinyu, L. Li","doi":"10.1117/12.2665559","DOIUrl":"https://doi.org/10.1117/12.2665559","url":null,"abstract":"The traditional moldy wheat identification and detection method require complex processing steps, which take a long time and have less feature extraction ability, resulting in poor moldy wheat identification and detection. In this paper, a F-C-BLS terahertz spectral image recognition method for moldy wheat is proposed based on broad learning system. The F-C-BLS moldy wheat classification and recognition model is constructed to enhance the image quality and improve the network feature extraction. Experimental results show that the classification accuracy of our F-C-BLS network is 5.11%, 5.27%, 3.89 and 4.06% higher than that of BLS, RF, CNN and RNN, respectively. Therefore, our algorithm can effectively provide a new and effective method for the early identification of wheat mold.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116396027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Through the passive observation and algorithm processing of the two-station infrared camera, the three-dimensional coordinates of the landing point of the shell are located, and the target is automatically reported throughout the day for the range training, which is an important way for training evaluation. The traditional photoelectric imaging target reporting method directly locates the double station based on the detection of the explosion point of the image shell, locates the three-dimensional position of the shell explosion point, and outputs the target reporting results. This method faces two difficulties. Firstly, because the ground in the image cannot provide enough geometric prior knowledge, the detection deviation of the shell explosion point in the image is large, resulting in the target reporting result based on the double station positioning of the shell explosion point cannot meet the 1m accuracy requirement. Secondly, due to the interference of the mushroom cloud at the pre-sequence shell blast point, the explosion point of the group shell is difficult to be effectively detected, so the method does not support the continuous target reporting of multiple bullets. Based on this, this paper proposes a range prediction target reporting algorithm, which is based on the detection of the shell's aerial trajectory for double-station positioning, first locates the three-dimensional track points of the shell target when it moves in the air, then fits out the three-dimensional trajectory of the shell in the air, and finally predicts the three-dimensional position of the shell explosion point based on the bulls eye GPS information, and outputs the target reporting results. The algorithm avoids the detection of image explosion points, which can improve the positioning accuracy of explosion points, and can avoid the interference of mushroom clouds at the explosion points of pre-sequence shells and realize the automatic target reporting of continuous shells. In addition, in view of the problem of matching between group shell stations, this paper adopts the method of multi-target matching target based on track direction estimation. Firstly, it performs single-frame multi-target preliminary matching based on the elevation difference of dual-station direction finding rays and obtains all three-dimensional track points in the air of each shell target. Then, based on the two-dimensional histogram of the direction or the Mean Shift algorithm, the three-dimensional track direction of each shell target is estimated, and the true and false track points are checked based on the three-dimensional track direction of the target, and the false matching points are eliminated. Finally, the three-dimensional trajectory fitting and the position prediction of the explosion point of the shell target are carried out, and the target reporting results are output. Experiments verify that the positioning error of a single shell in this algorithm is 0.57m, and the positio
{"title":"A multi-shells prediction target reporting algorithm based on aerial three-dimensional trajectory estimation","authors":"Juan Yue, Jie Liu, Sili Gao","doi":"10.1117/12.2664646","DOIUrl":"https://doi.org/10.1117/12.2664646","url":null,"abstract":"Through the passive observation and algorithm processing of the two-station infrared camera, the three-dimensional coordinates of the landing point of the shell are located, and the target is automatically reported throughout the day for the range training, which is an important way for training evaluation. The traditional photoelectric imaging target reporting method directly locates the double station based on the detection of the explosion point of the image shell, locates the three-dimensional position of the shell explosion point, and outputs the target reporting results. This method faces two difficulties. Firstly, because the ground in the image cannot provide enough geometric prior knowledge, the detection deviation of the shell explosion point in the image is large, resulting in the target reporting result based on the double station positioning of the shell explosion point cannot meet the 1m accuracy requirement. Secondly, due to the interference of the mushroom cloud at the pre-sequence shell blast point, the explosion point of the group shell is difficult to be effectively detected, so the method does not support the continuous target reporting of multiple bullets. Based on this, this paper proposes a range prediction target reporting algorithm, which is based on the detection of the shell's aerial trajectory for double-station positioning, first locates the three-dimensional track points of the shell target when it moves in the air, then fits out the three-dimensional trajectory of the shell in the air, and finally predicts the three-dimensional position of the shell explosion point based on the bulls eye GPS information, and outputs the target reporting results. The algorithm avoids the detection of image explosion points, which can improve the positioning accuracy of explosion points, and can avoid the interference of mushroom clouds at the explosion points of pre-sequence shells and realize the automatic target reporting of continuous shells. In addition, in view of the problem of matching between group shell stations, this paper adopts the method of multi-target matching target based on track direction estimation. Firstly, it performs single-frame multi-target preliminary matching based on the elevation difference of dual-station direction finding rays and obtains all three-dimensional track points in the air of each shell target. Then, based on the two-dimensional histogram of the direction or the Mean Shift algorithm, the three-dimensional track direction of each shell target is estimated, and the true and false track points are checked based on the three-dimensional track direction of the target, and the false matching points are eliminated. Finally, the three-dimensional trajectory fitting and the position prediction of the explosion point of the shell target are carried out, and the target reporting results are output. Experiments verify that the positioning error of a single shell in this algorithm is 0.57m, and the positio","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124051657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
You-Long Chen, Xing-yuan Zhang, Yi-Hua Hu, Yu-Shuang Zhang, Sheng-Jie Ma
With the increasing frequency of space activities, space satellite systems are fully involved in joint operations. Numerous imaging and reconnaissance optical imaging satellite systems are arduous to evade and warn actively, and passive protection is cumbersome to implement. Therefore, developing new reflective imaging satellite reconnaissance systems and materials is particularly important. In countering optical imaging satellites, active jamming materials can form aerosol jamming smoke screens on the action path of the target to be protected. The jamming signal transmitted in all directions can suppress the imaging accuracy of the optical satellite to the target and form an effective deception. CsPbBr3 perovskite quantum dots show great potential in anti-detection and active jamming due to their high absorption and emission efficiency, size-dependent excellent photoelectric properties, and low exciton binding energy. However, it is still challenging to synthesize CsPbBr3 nanosheets with wide band emission for active interference. This paper uses the template induction method to regulate the morphology of the CsPbBr3 crystal. CsPbBr3 nanospheres and nanocubes were synthesized by the recrystallization method. CsPbBr3 nanospheres were induced to self-assemble on CsPbBr3 nanocubes to synthesize CsPbBr3 nanosheets with wideband emissions. It maintained a strong quantum confinement effect, a simple synthesis process, high stability, and excellent photoelectric performance. The induced synthesis process was recorded by field emission transmission electron microscope. The nanosheets were face-to-face, close, and perpendicular to the carbon film substrate. The balance of van der Waals force and elastic repulsion force between ligands under thermodynamics determines the lamellar spacing of nanosheets in the self-assembled state. UV-Vi's absorption spectra further proved the change of morphology during self-assembly. The nanosheets were also very stable under 200kV electron beam bombardment. The fast Fourier transform patterns of the nanosheet demonstrated that the assembled NCs were orthogonal, with no crystal transition in the assembly process. X-ray photoelectron spectroscopy showed that the crystal is composed of CS, Pb, and Br elements. The assembly process did not change the ion state and element composition on the surface and inside. The photoluminescence spectrum showed that the emission wavelength of the nanosheets was 493nm, and a uniformly tunable emission wavelength was generated between 468-506nm. The disappearance of the tail band in the long wavelength region demonstrated that the defects in the self-assembly process were significantly reduced. The quantum yield increased from 65.78% to 67.33%, which directly confirmed that the large absorption cross section and defect reduction brought by the unique sheet structure were conducive to the conversion of excitation light in the active interference process. This paper provides an idea for the t
{"title":"Self-assembled CsPbBr3 quantum nanosheet for optical reconnaissance satellite active jamming","authors":"You-Long Chen, Xing-yuan Zhang, Yi-Hua Hu, Yu-Shuang Zhang, Sheng-Jie Ma","doi":"10.1117/12.2665449","DOIUrl":"https://doi.org/10.1117/12.2665449","url":null,"abstract":"With the increasing frequency of space activities, space satellite systems are fully involved in joint operations. Numerous imaging and reconnaissance optical imaging satellite systems are arduous to evade and warn actively, and passive protection is cumbersome to implement. Therefore, developing new reflective imaging satellite reconnaissance systems and materials is particularly important. In countering optical imaging satellites, active jamming materials can form aerosol jamming smoke screens on the action path of the target to be protected. The jamming signal transmitted in all directions can suppress the imaging accuracy of the optical satellite to the target and form an effective deception. CsPbBr3 perovskite quantum dots show great potential in anti-detection and active jamming due to their high absorption and emission efficiency, size-dependent excellent photoelectric properties, and low exciton binding energy. However, it is still challenging to synthesize CsPbBr3 nanosheets with wide band emission for active interference. This paper uses the template induction method to regulate the morphology of the CsPbBr3 crystal. CsPbBr3 nanospheres and nanocubes were synthesized by the recrystallization method. CsPbBr3 nanospheres were induced to self-assemble on CsPbBr3 nanocubes to synthesize CsPbBr3 nanosheets with wideband emissions. It maintained a strong quantum confinement effect, a simple synthesis process, high stability, and excellent photoelectric performance. The induced synthesis process was recorded by field emission transmission electron microscope. The nanosheets were face-to-face, close, and perpendicular to the carbon film substrate. The balance of van der Waals force and elastic repulsion force between ligands under thermodynamics determines the lamellar spacing of nanosheets in the self-assembled state. UV-Vi's absorption spectra further proved the change of morphology during self-assembly. The nanosheets were also very stable under 200kV electron beam bombardment. The fast Fourier transform patterns of the nanosheet demonstrated that the assembled NCs were orthogonal, with no crystal transition in the assembly process. X-ray photoelectron spectroscopy showed that the crystal is composed of CS, Pb, and Br elements. The assembly process did not change the ion state and element composition on the surface and inside. The photoluminescence spectrum showed that the emission wavelength of the nanosheets was 493nm, and a uniformly tunable emission wavelength was generated between 468-506nm. The disappearance of the tail band in the long wavelength region demonstrated that the defects in the self-assembly process were significantly reduced. The quantum yield increased from 65.78% to 67.33%, which directly confirmed that the large absorption cross section and defect reduction brought by the unique sheet structure were conducive to the conversion of excitation light in the active interference process. This paper provides an idea for the t","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117014511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maosheng Sang, Fan Yang, Guoqing Xu, H. Qiao, Xiaoyang Yang, Xiangyang Li, P. Yang, Dahui Wang
The laser response of HgCdTe medium-wave photovoltaic device is numerically simulated in this research. The simulations are carried out by considering the carrier electrical properties and a simulation model is obtained, and simulation results are in general conformity with the experimental results under both strong and weak illumination. The saturation threshold increases as the operating temperature of the device decreases, according to the current response characteristics of the device. The contact resistance of device is calculated and discussed, and the optimized device structure are given to point out the direction of parameter optimization. Furthermore, two-dimensional simulations demonstrate that the electrode size and composition gradient and reverse voltage has a considerable impact on the photocurrent, which is an essential problem to address in the development of high saturation threshold mid-wave infrared HgCdTe photovoltaic devices.
{"title":"Two-dimensional modeling of the saturation characteristics of laser irradiation on HgCdTe mid-wave infrared photovoltaic devices","authors":"Maosheng Sang, Fan Yang, Guoqing Xu, H. Qiao, Xiaoyang Yang, Xiangyang Li, P. Yang, Dahui Wang","doi":"10.1117/12.2665517","DOIUrl":"https://doi.org/10.1117/12.2665517","url":null,"abstract":"The laser response of HgCdTe medium-wave photovoltaic device is numerically simulated in this research. The simulations are carried out by considering the carrier electrical properties and a simulation model is obtained, and simulation results are in general conformity with the experimental results under both strong and weak illumination. The saturation threshold increases as the operating temperature of the device decreases, according to the current response characteristics of the device. The contact resistance of device is calculated and discussed, and the optimized device structure are given to point out the direction of parameter optimization. Furthermore, two-dimensional simulations demonstrate that the electrode size and composition gradient and reverse voltage has a considerable impact on the photocurrent, which is an essential problem to address in the development of high saturation threshold mid-wave infrared HgCdTe photovoltaic devices.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"270 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115966404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Methane is the second largest greenhouse gas after carbon dioxide, and the measurement and monitoring of methane is essential for regional and city-scale emission reduction strategies. Atmospheric methane concentration observations are also important for predicting regional emission trends. Spectrometers are important optical instruments for monitoring the content of greenhouse gases in the atmosphere, and most spectrometers choose a grating as the spectroscopic element. Due to the higher resolution of the immersion grating, it reduces its volume while improving the performance of the spectrometer and reducing the weight of the whole machine, so it is of great significance to study the immersion grating for the practical application of the spectrometer. In this paper, the quartz immersed grating was designed for weak CH4 band. The rectangular groove structure with high refractive index dielectric film was designed in consideration of possible fabrication errors. In the 2.275-2.325μm band, the duty cycle of the rectangular groove is 0.3~0.45, the thickness of TiO2 is 165~170nm and the groove depth is in the 800~980nm region, the diffraction efficiency of the grating is higher than 70%. When the thickness of TiO2 is 170nm and the groove depth is in the 800~950 nm region, the diffraction efficiency of the grating is higher than 80%. When the TiO2 thickness is 175~180 nm, the overall polarization degree is less than 0.1. For trapezoidal grooves, when the duty cycle is 0.3~0.35, the bottom angle of the trapezoid is 80°~86°, the thickness of TiO2 is 195 nm, the depth of the grating groove is 820~900nm, and the diffraction efficiency can be above 80%. When the thickness of TiO2 is 177~195nm, the polarization degree is less than 0.1. The TiO2 film will be deposited by atomic layer deposition.
{"title":"Study on immersion grating for methane detection spectrometer","authors":"Zhou Nenghua, Quan Liu, B. Huang","doi":"10.1117/12.2665330","DOIUrl":"https://doi.org/10.1117/12.2665330","url":null,"abstract":"Methane is the second largest greenhouse gas after carbon dioxide, and the measurement and monitoring of methane is essential for regional and city-scale emission reduction strategies. Atmospheric methane concentration observations are also important for predicting regional emission trends. Spectrometers are important optical instruments for monitoring the content of greenhouse gases in the atmosphere, and most spectrometers choose a grating as the spectroscopic element. Due to the higher resolution of the immersion grating, it reduces its volume while improving the performance of the spectrometer and reducing the weight of the whole machine, so it is of great significance to study the immersion grating for the practical application of the spectrometer. In this paper, the quartz immersed grating was designed for weak CH4 band. The rectangular groove structure with high refractive index dielectric film was designed in consideration of possible fabrication errors. In the 2.275-2.325μm band, the duty cycle of the rectangular groove is 0.3~0.45, the thickness of TiO2 is 165~170nm and the groove depth is in the 800~980nm region, the diffraction efficiency of the grating is higher than 70%. When the thickness of TiO2 is 170nm and the groove depth is in the 800~950 nm region, the diffraction efficiency of the grating is higher than 80%. When the TiO2 thickness is 175~180 nm, the overall polarization degree is less than 0.1. For trapezoidal grooves, when the duty cycle is 0.3~0.35, the bottom angle of the trapezoid is 80°~86°, the thickness of TiO2 is 195 nm, the depth of the grating groove is 820~900nm, and the diffraction efficiency can be above 80%. When the thickness of TiO2 is 177~195nm, the polarization degree is less than 0.1. The TiO2 film will be deposited by atomic layer deposition.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"235 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126242131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hg1-xCdxTe is considered as the preferred material for high performance infrared photodetectors and imaging focal plane array (FPA) detectors. One of the technical challenges of multi-dimensional integrated HgCdTe epitaxy by molecular beam epitaxy (MBE) lies in the in-situ extraction, characterization and precisely control of a series of parameters such as alloy composition, surface roughness, substrate temperature and film thickness at a relatively low substrate temperature of about 180°C. Therefore, an in-situ, nondestructive spectroscopic ellipsometry (SE) method is needed to characterize the performance of HgCdTe films. In this paper, real time optical property characterization of short-wave Hg1-xCdxTe epitaxial grown by MBE is reported. Run to run feasibility and stability of in-situ SE is confirmed by buffer layer thickness verification in multiple growth runs. Lorentz oscillator parametric model provides a new approach to describe optical dispersion property of HgCdTe over spectral range of 1.5-4.1 eV. The absorption peaks show blue shift with the increase of HgCdTe Cd composition (x). Under this circumstance, the longitudinal x value for HgCdTe during epitaxy process can be obtained in real time without any surface damage by successfully building a composition-dependent optical constant library, with routine run-to-run reproducibility measurement accuracy Δx of ~ 0.0015. This work will facilitate the fabrication of HgCdTe heterojunctions with complex component distribution and doping profiles.
{"title":"In-situ ellipsometric study on composition-dependent short-wave HgCdTe in the process of molecular beam epitaxy growth","authors":"Liao Yang, Chuan Shen, Lu Chen, Li He","doi":"10.1117/12.2664815","DOIUrl":"https://doi.org/10.1117/12.2664815","url":null,"abstract":"Hg1-xCdxTe is considered as the preferred material for high performance infrared photodetectors and imaging focal plane array (FPA) detectors. One of the technical challenges of multi-dimensional integrated HgCdTe epitaxy by molecular beam epitaxy (MBE) lies in the in-situ extraction, characterization and precisely control of a series of parameters such as alloy composition, surface roughness, substrate temperature and film thickness at a relatively low substrate temperature of about 180°C. Therefore, an in-situ, nondestructive spectroscopic ellipsometry (SE) method is needed to characterize the performance of HgCdTe films. In this paper, real time optical property characterization of short-wave Hg1-xCdxTe epitaxial grown by MBE is reported. Run to run feasibility and stability of in-situ SE is confirmed by buffer layer thickness verification in multiple growth runs. Lorentz oscillator parametric model provides a new approach to describe optical dispersion property of HgCdTe over spectral range of 1.5-4.1 eV. The absorption peaks show blue shift with the increase of HgCdTe Cd composition (x). Under this circumstance, the longitudinal x value for HgCdTe during epitaxy process can be obtained in real time without any surface damage by successfully building a composition-dependent optical constant library, with routine run-to-run reproducibility measurement accuracy Δx of ~ 0.0015. This work will facilitate the fabrication of HgCdTe heterojunctions with complex component distribution and doping profiles.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130211249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photodetectors convert optical signals into electrical signals and have found many important applications ranging from environmental monitoring to communication systems. At present, most photodetectors are based on either bulk materials or epitaxially grown materials (such as InSb and HgCdTe), which limit its widespread applications due to relatively high fabrication cost. However, photodetector based on organic polymer/colloidal quantum dots (CQDs) can provide a low-cost alternative. In this paper, a broadband photodetector consisting of organic polymer phenyl-c61-butyric acid methyl ester (PCBM) and PbS CQDs was fabricated. Combining the advantages of PbS CQDs and organic polymer PCBM, the device demonstrated good spectral response ranging from the UV to the NIR with a maximum responsivity and detectivity of 0.3 A/W and 6.6 × 1011 Jones, respectively, under illumination of 850 nm incident light. The device can be fabricated on almost any substrate due to the solution-processibility of CQDs. Furthermore, the use of organic polymer substrate can significantly reduce the cost of device and broaden its applications (such as in flexible electronics). This work provides a simple and efficient strategy to fabricate photodetector that exhibits multi-band response at relatively low-cost.
光电探测器将光信号转换为电信号，并在从环境监测到通信系统的许多重要应用中得到了应用。目前，大多数光电探测器都是基于块体材料或外延生长材料(如InSb和HgCdTe)，由于制造成本相对较高，限制了其广泛应用。然而，基于有机聚合物/胶体量子点(CQDs)的光电探测器可以提供一种低成本的替代方案。本文制备了一种由有机聚合物苯基-c61-丁酸甲酯(PCBM)和PbS CQDs组成的宽带光电探测器。该器件结合了PbS CQDs和有机聚合物PCBM的优点，在850 nm入射光照射下，在紫外到近红外范围内表现出良好的光谱响应，最大响应率和探测率分别为0.3 a /W和6.6 × 1011 Jones。由于CQDs的溶液可加工性，该器件可以在几乎任何衬底上制造。此外，有机聚合物衬底的使用可以显著降低器件成本并拓宽其应用范围(如柔性电子)。这项工作提供了一种简单有效的策略，以相对低的成本制造出具有多波段响应的光电探测器。
{"title":"Solution-processed PbS colloidal quantum dots/PCBM based photodetector for multispectral detection","authors":"Lijing Yu, P. Tian, L. Tang, Qun Hao, K. Teng","doi":"10.1117/12.2665265","DOIUrl":"https://doi.org/10.1117/12.2665265","url":null,"abstract":"Photodetectors convert optical signals into electrical signals and have found many important applications ranging from environmental monitoring to communication systems. At present, most photodetectors are based on either bulk materials or epitaxially grown materials (such as InSb and HgCdTe), which limit its widespread applications due to relatively high fabrication cost. However, photodetector based on organic polymer/colloidal quantum dots (CQDs) can provide a low-cost alternative. In this paper, a broadband photodetector consisting of organic polymer phenyl-c61-butyric acid methyl ester (PCBM) and PbS CQDs was fabricated. Combining the advantages of PbS CQDs and organic polymer PCBM, the device demonstrated good spectral response ranging from the UV to the NIR with a maximum responsivity and detectivity of 0.3 A/W and 6.6 × 1011 Jones, respectively, under illumination of 850 nm incident light. The device can be fabricated on almost any substrate due to the solution-processibility of CQDs. Furthermore, the use of organic polymer substrate can significantly reduce the cost of device and broaden its applications (such as in flexible electronics). This work provides a simple and efficient strategy to fabricate photodetector that exhibits multi-band response at relatively low-cost.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128023638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lu Lee, Chengli Qi, L. Ding, Peng Zhang, Xiuqing Hu, Mingjian Gu, Tianhang Yang
The infrared (IR) benchmark sounder is designed to detect the tiny change of long-term global climate by measuring the spectrally resolved IR radiance emitted from Earth to space with high accuracy. Besides, the IR sounder also serve as a space-borne radiometric reference to convert the international fleet of weather sounders into a climate benchmarking system with excellent global coverage and similar measurement accuracy. In order to achieve high accuracy, the benchmark sounder must be tuned to be a linear response system and be well radiometrically calibrated. So the nonlinearity response in an IR detector signal chain needs to be corrected prior to the linear radiometric calibration. There are some algorithmic approaches being commonly used to correct the nonlinear measurements. These methods use the measured nonlinear interferograms to polynomially fit the corrected linear interferograms, without considering the physical root of non-linearity. However, they work well only when the detector nonlinearity is small. Regarding the large nonlinearity, a correction method is proposed in this paper. It follows the nonlinearity response mechanism of the IR detector, and uses the to-be-solved linear interferogram to polynomially fit the measured non-linear interferogram signal formally, and then derive the correction coefficients from the established equations. According to the correction evaluation and methods comparison using the simulated data as proxy measurements, the proposed method is appropriate for both small and large degree of quadratic nonlinearity detectors.
{"title":"Radiometric nonlinearity and the correction strategies for infrared hyperspectral benchmark sounder","authors":"Lu Lee, Chengli Qi, L. Ding, Peng Zhang, Xiuqing Hu, Mingjian Gu, Tianhang Yang","doi":"10.1117/12.2665585","DOIUrl":"https://doi.org/10.1117/12.2665585","url":null,"abstract":"The infrared (IR) benchmark sounder is designed to detect the tiny change of long-term global climate by measuring the spectrally resolved IR radiance emitted from Earth to space with high accuracy. Besides, the IR sounder also serve as a space-borne radiometric reference to convert the international fleet of weather sounders into a climate benchmarking system with excellent global coverage and similar measurement accuracy. In order to achieve high accuracy, the benchmark sounder must be tuned to be a linear response system and be well radiometrically calibrated. So the nonlinearity response in an IR detector signal chain needs to be corrected prior to the linear radiometric calibration. There are some algorithmic approaches being commonly used to correct the nonlinear measurements. These methods use the measured nonlinear interferograms to polynomially fit the corrected linear interferograms, without considering the physical root of non-linearity. However, they work well only when the detector nonlinearity is small. Regarding the large nonlinearity, a correction method is proposed in this paper. It follows the nonlinearity response mechanism of the IR detector, and uses the to-be-solved linear interferogram to polynomially fit the measured non-linear interferogram signal formally, and then derive the correction coefficients from the established equations. According to the correction evaluation and methods comparison using the simulated data as proxy measurements, the proposed method is appropriate for both small and large degree of quadratic nonlinearity detectors.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"22 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128442339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The targets on the earth can be detected by its radiation in thermal band from the remote sensing satellite day and night. The State-of-the-art infrared detector technology makes it possible to use thermal focal plane array (FPA) to probe interested target in the boundless sea. Unfortunately due to accidental and uncontrollable factors during detector production, there always are defective detectors in the thermal focal plane array, more or less. We can call it dark element if it has no or weaker response, or can call it hot element if it has abnormal stronger response. These two kinds of defective response cannot be mitigated by linearity correcting, contrarily it will be harmful to the target detecting. Method to identify these defective detectors by analyzing their frequency domain characteristics is stated here. The recognition rate of defective detectors is greater than 98% by using such method.
{"title":"Method to identify defective detectors of thermal focal plane array based on its frequency domain characteristics","authors":"Xiaoxian Huang, Feifei Xu, Yutian Fu","doi":"10.1117/12.2665554","DOIUrl":"https://doi.org/10.1117/12.2665554","url":null,"abstract":"The targets on the earth can be detected by its radiation in thermal band from the remote sensing satellite day and night. The State-of-the-art infrared detector technology makes it possible to use thermal focal plane array (FPA) to probe interested target in the boundless sea. Unfortunately due to accidental and uncontrollable factors during detector production, there always are defective detectors in the thermal focal plane array, more or less. We can call it dark element if it has no or weaker response, or can call it hot element if it has abnormal stronger response. These two kinds of defective response cannot be mitigated by linearity correcting, contrarily it will be harmful to the target detecting. Method to identify these defective detectors by analyzing their frequency domain characteristics is stated here. The recognition rate of defective detectors is greater than 98% by using such method.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128458969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
InGaAs/InP single photon avalanche photodiode (SPAD) is important for quantum communication, and LIDAR applications in the near-infrared (NIR) wavelength range, between 0.9 µm and 1.7 µm. Compared with other optoelectronic devices, SPAD has two main advantages: high quantum efficiency and high detection efficiency. In this study, the design and simulating of a separate absorption, grading, charge, and multiplication (SAGCM) structure InGaAs/InP SPAD were conducted by using COMSOL Multiphysics. The electric-field distribution was studied under the given thickness and dopant concentration of each layer of the SPAD. It was found that the edge pre-breakdown of planar-type SPAD resulted from the intense electric field at the junction bend can be prevent from happening by using gaussian type dopant distribution profile. The punch-through voltage and the breakdown voltage were also focused. The results show that the punch-through voltage and the breakdown voltage was 55 V and 65V respectively. In addition, the electric field nonuniformity of the avalanche area increases greatly after the bias voltage exceeded the punch-through voltage.
{"title":"Simulation of SAGCM structure InGaAs/InP SPAD using COMSOL multiphysics","authors":"Rui Yang","doi":"10.1117/12.2664526","DOIUrl":"https://doi.org/10.1117/12.2664526","url":null,"abstract":"InGaAs/InP single photon avalanche photodiode (SPAD) is important for quantum communication, and LIDAR applications in the near-infrared (NIR) wavelength range, between 0.9 µm and 1.7 µm. Compared with other optoelectronic devices, SPAD has two main advantages: high quantum efficiency and high detection efficiency. In this study, the design and simulating of a separate absorption, grading, charge, and multiplication (SAGCM) structure InGaAs/InP SPAD were conducted by using COMSOL Multiphysics. The electric-field distribution was studied under the given thickness and dopant concentration of each layer of the SPAD. It was found that the edge pre-breakdown of planar-type SPAD resulted from the intense electric field at the junction bend can be prevent from happening by using gaussian type dopant distribution profile. The punch-through voltage and the breakdown voltage were also focused. The results show that the punch-through voltage and the breakdown voltage was 55 V and 65V respectively. In addition, the electric field nonuniformity of the avalanche area increases greatly after the bias voltage exceeded the punch-through voltage.","PeriodicalId":258680,"journal":{"name":"Earth and Space From Infrared to Terahertz (ESIT 2022)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114372581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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