For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LB...For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LBIC microscopy, also generally called photocurrent mapping(PC mapping), can provide spatially resolved information about local electrical properties and p-n junction formation in photovoltaic infrared(including visible light) photodetectors from which it is possible to extract material and device parameters such as junction area, junction depth, diffusion length, leakage current position and minority carrier diffusion length etc. This paper presents a comprehensive review of research background, operating principle, fundamental issues, and applications of LBIC or PC mapping.展开更多
A medium wave(MW)640×512(25μm)Mercury Cadmium Telluride(HgCdTe)polarimetric focal plane array(FPA)was demonstrated.The micro-polarizer array(MPA)has been carefully designed in terms of line grating structure opt...A medium wave(MW)640×512(25μm)Mercury Cadmium Telluride(HgCdTe)polarimetric focal plane array(FPA)was demonstrated.The micro-polarizer array(MPA)has been carefully designed in terms of line grating structure optimization and crosstalk suppression.A monolithic fabrication process with low damage was explored,which was verified to be compatible well with HgCdTe devices.After monolithic integration of MPA,NETD<9.5 mK was still maintained.Furthermore,to figure out the underlying mechanism that dominat⁃ed the extinction ratio(ER),specialized MPA layouts were designed,and the crosstalk was experimentally vali⁃dated as the major source that impacted ER.By expanding opaque regions at pixel edges to 4μm,crosstalk rates from adjacent pixels could be effectively reduced to approximately 2%,and promising ERs ranging from 17.32 to 27.41 were implemented.展开更多
Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status,which offers another degree of freedom in infrared remote sensing.However,to ...Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status,which offers another degree of freedom in infrared remote sensing.However,to scale up by monolithically integrating grating-based polarizers onto a focal plane array(FPA)of infrared detectors,fundamental technical obstacles must be overcome,including reductions of the extinction ratio by the misalignment between the polarizer and the detector,grating line width fluctuations,the line edge roughness,etc.This paper reports the authors’latest achievements in overcoming those problems by solving key technical issues regarding the integration of large-scale polarizers onto the chips of FPAs with individual indium gallium arsenide/indium phosphide(In Ga As/In P)sensors as the basic building blocks.Polarimetric and photovoltaic chips with divisions of the focal plane of 540×4 pixels and 320×256 superpixels have been successfully manufactured.Polarimetric imaging with enhanced contrast has been demonstrated.The progress made in this work has opened up a broad avenue toward industrialization of high quality polarimetric imaging in infrared wavelengths.展开更多
The variational statement of synthesis problem is generalized in order to account the additional requirements to the synthesized radiation pattern (RP) and field distribution in the specified points of near zone. For ...The variational statement of synthesis problem is generalized in order to account the additional requirements to the synthesized radiation pattern (RP) and field distribution in the specified points of near zone. For this aim, the minimizing functional is supplemented by term providing the possibility to minimize the values of field in these points;creating the deep zeros in the RP for the certain angular coordinates is realized too. The approach foresees reduction of an explicit formula for field values in a near zone. The results of computational modeling testify the possibility to create zeros in the given RP and to minimize the values of field in a near zone of plane arrays in a great extent.展开更多
This work focuses on the performance comparison of monocrystalline and polycrystalline Si solar photovoltaic(SPV)modules under tropical wet and dry climatic conditions in east-central India(21.16°N 81.65°E,R...This work focuses on the performance comparison of monocrystalline and polycrystalline Si solar photovoltaic(SPV)modules under tropical wet and dry climatic conditions in east-central India(21.16°N 81.65°E,Raipur,Chhattisgarh).This study would help to select the SPV module for system installation in the east-central part of the country.For comparative analysis,we used performance ratio(PR)and efficiency as figures of merit.The plane-of-array(POA)irradiance was used to determine the efficiency of the modules.The decomposition and transposition models calculated the POA values from the measured global horizontal irradiance.The data were analysed systematically for 6 months in the non-rainy season,from October 2020 to March 2021.Special attention was given to solar irradiance,ambient temperature and module temperature-the parameters that affect the performance of PV modules.The month of October showed the highest variation in irradiance and temperature.The highest average module temperatures(51-52℃)were observed in October-November,while the lowest average module temperatures(34℃ for mono-Si and 36℃ for poly-Si)were observed in December.The highest value of average monthly POA irradiance(568 W/m^(2))was observed in February and the lowest(483 W/m^(2))in December.The results showed that the monocrystalline SPV module performed better than the polycrystalline module under all weather conditions.The maximum observed values of mono-Si and poly-Si panel PRs were 0.89 and 0.86,respectively,in December.展开更多
On the basis of opto-mechanical effect and micro electromechanical system(MEMS)technology,a novel substrate-free focal plane array(FPA)with the thermal isolated structure for uncooled infrared imaging is developed,eve...On the basis of opto-mechanical effect and micro electromechanical system(MEMS)technology,a novel substrate-free focal plane array(FPA)with the thermal isolated structure for uncooled infrared imaging is developed,even as alternate evaporated Au on SiN cantilever is used for thermal isolation.A human thermal image is obtained successfully by using the infrared imaging system composed of the FPA and optical detecting system.The experiment results show that the realization of thermal isolation structure in substrate-free FPA increases the temperature rise of the deflecting leg effectively,whereas the noise equivalent temperature difference(NETD)is about 200 mK.展开更多
基金supported by the State Key Program for Basic Research of China(Grant No.2014CB921600)the National Natural Science Foundation of China(Grant Nos.11322441 and 11274331)the Fund of Shanghai Science and Technology Foundation(Grant No.14JC1406400)
文摘For non-destructive optical characterization, laser beam induced current(LBIC) microscopy has been developed into as a quantitative tool to examine individual photodiodes within a large pixel array. Two-dimensional LBIC microscopy, also generally called photocurrent mapping(PC mapping), can provide spatially resolved information about local electrical properties and p-n junction formation in photovoltaic infrared(including visible light) photodetectors from which it is possible to extract material and device parameters such as junction area, junction depth, diffusion length, leakage current position and minority carrier diffusion length etc. This paper presents a comprehensive review of research background, operating principle, fundamental issues, and applications of LBIC or PC mapping.
基金Supported by the self-funded project of Kunming Institute of Physics。
文摘A medium wave(MW)640×512(25μm)Mercury Cadmium Telluride(HgCdTe)polarimetric focal plane array(FPA)was demonstrated.The micro-polarizer array(MPA)has been carefully designed in terms of line grating structure optimization and crosstalk suppression.A monolithic fabrication process with low damage was explored,which was verified to be compatible well with HgCdTe devices.After monolithic integration of MPA,NETD<9.5 mK was still maintained.Furthermore,to figure out the underlying mechanism that dominat⁃ed the extinction ratio(ER),specialized MPA layouts were designed,and the crosstalk was experimentally vali⁃dated as the major source that impacted ER.By expanding opaque regions at pixel edges to 4μm,crosstalk rates from adjacent pixels could be effectively reduced to approximately 2%,and promising ERs ranging from 17.32 to 27.41 were implemented.
文摘针对信号相位匹配奇异值分解(SVDSPM)算法中参数联合估计耗时长的问题,提出了免疫记忆量子克隆算法(IMQCA).该优化算法引入模拟退火机制修正量子旋转门函数的旋转角度值,构建记忆单元保留进化历史最佳抗体,并结合克隆算子加速种群收敛.由SVDSPM平面阵算法构造了IMQCA的目标函数,提出了同时估计信号方位角、俯仰角和频率的SVDSPM联合估计算法.仿真结果表明,IMQCA算法的方位估计精度与传统的SVDSPM算法相当,但计算耗时仅约为后者的10%,且低信噪比下的性能优于MUSIC方法.在-10 dB信噪比下,IMQCA所得方位角、俯仰角和频率的标准差分别比标准遗传算法小6.659°、9.645°和28.634 Hz,比量子免疫克隆算法小0.789°、1.075°和0.864 Hz.
基金financially supported by the following projects:Open project of SITP(Project Number:IIMDKFJJ-18-09)National Natural Science Foundation of China(Project Number:61927820)+2 种基金The STCSM2019-11-20 funding(Project Number:19142202700)National Natural Science Foundation of China(Project Number:NSF No.U1732104)Zhejiang Lab’s International Talent Fund for Young Professionals。
文摘Polarimetric imaging enhances the ability to distinguish objects from a bright background by detecting their particular polarization status,which offers another degree of freedom in infrared remote sensing.However,to scale up by monolithically integrating grating-based polarizers onto a focal plane array(FPA)of infrared detectors,fundamental technical obstacles must be overcome,including reductions of the extinction ratio by the misalignment between the polarizer and the detector,grating line width fluctuations,the line edge roughness,etc.This paper reports the authors’latest achievements in overcoming those problems by solving key technical issues regarding the integration of large-scale polarizers onto the chips of FPAs with individual indium gallium arsenide/indium phosphide(In Ga As/In P)sensors as the basic building blocks.Polarimetric and photovoltaic chips with divisions of the focal plane of 540×4 pixels and 320×256 superpixels have been successfully manufactured.Polarimetric imaging with enhanced contrast has been demonstrated.The progress made in this work has opened up a broad avenue toward industrialization of high quality polarimetric imaging in infrared wavelengths.
文摘The variational statement of synthesis problem is generalized in order to account the additional requirements to the synthesized radiation pattern (RP) and field distribution in the specified points of near zone. For this aim, the minimizing functional is supplemented by term providing the possibility to minimize the values of field in these points;creating the deep zeros in the RP for the certain angular coordinates is realized too. The approach foresees reduction of an explicit formula for field values in a near zone. The results of computational modeling testify the possibility to create zeros in the given RP and to minimize the values of field in a near zone of plane arrays in a great extent.
文摘This work focuses on the performance comparison of monocrystalline and polycrystalline Si solar photovoltaic(SPV)modules under tropical wet and dry climatic conditions in east-central India(21.16°N 81.65°E,Raipur,Chhattisgarh).This study would help to select the SPV module for system installation in the east-central part of the country.For comparative analysis,we used performance ratio(PR)and efficiency as figures of merit.The plane-of-array(POA)irradiance was used to determine the efficiency of the modules.The decomposition and transposition models calculated the POA values from the measured global horizontal irradiance.The data were analysed systematically for 6 months in the non-rainy season,from October 2020 to March 2021.Special attention was given to solar irradiance,ambient temperature and module temperature-the parameters that affect the performance of PV modules.The month of October showed the highest variation in irradiance and temperature.The highest average module temperatures(51-52℃)were observed in October-November,while the lowest average module temperatures(34℃ for mono-Si and 36℃ for poly-Si)were observed in December.The highest value of average monthly POA irradiance(568 W/m^(2))was observed in February and the lowest(483 W/m^(2))in December.The results showed that the monocrystalline SPV module performed better than the polycrystalline module under all weather conditions.The maximum observed values of mono-Si and poly-Si panel PRs were 0.89 and 0.86,respectively,in December.
基金supported by the National Natural Science Foundation of China(Grant No.60236010)the National Technology Research Development Program of China(No.2005AA404210).
文摘On the basis of opto-mechanical effect and micro electromechanical system(MEMS)technology,a novel substrate-free focal plane array(FPA)with the thermal isolated structure for uncooled infrared imaging is developed,even as alternate evaporated Au on SiN cantilever is used for thermal isolation.A human thermal image is obtained successfully by using the infrared imaging system composed of the FPA and optical detecting system.The experiment results show that the realization of thermal isolation structure in substrate-free FPA increases the temperature rise of the deflecting leg effectively,whereas the noise equivalent temperature difference(NETD)is about 200 mK.
