为提高长波红外偏振成像系统中偏振器件性能,本文通过分析光栅材料及结构参数对光栅偏振性能的影响,设计并优化了一种双层材料构成的亚波长光栅。该光栅为矩形形貌,光栅区由铝与硒化锌构成,两种材料的厚度分别为0.6μm和0.4μm,光栅周期...为提高长波红外偏振成像系统中偏振器件性能,本文通过分析光栅材料及结构参数对光栅偏振性能的影响,设计并优化了一种双层材料构成的亚波长光栅。该光栅为矩形形貌,光栅区由铝与硒化锌构成,两种材料的厚度分别为0.6μm和0.4μm,光栅周期1μm,占空比50%。利用严格耦合波理论分析并计算该结构光栅的衍射效率,7~15μm波段的光以0~60°入射后其0级横磁模透射率达到87.54%以上,消光比超过47 d B。该光栅在10.6μm的测试波长下,TM透射率高达90.80%且具有50 d B以上的消光比,相比槽深相同的单层铝光栅,偏振透过率明显提高。仿真结果显示,该光栅在整个宽长波红外波段具有良好的偏振性能。展开更多
Pixel-wise Code Exposure (PCE) camera is one type of compressive sensing camera that has low power consumption and high compression ratio. Moreover, a PCE camera can control individual pixel exposure time that can ena...Pixel-wise Code Exposure (PCE) camera is one type of compressive sensing camera that has low power consumption and high compression ratio. Moreover, a PCE camera can control individual pixel exposure time that can enable high dynamic range. Conventional approaches of using PCE camera involve a time consuming and lossy process to reconstruct the original frames and then use those frames for target tracking and classification. In this paper, we present a deep learning approach that directly performs target tracking and classification in the compressive measurement domain without any frame reconstruction. Our approach has two parts: tracking and classification. The tracking has been done using YOLO (You Only Look Once) and the classification is achieved using Residual Network (ResNet). Extensive experiments using mid-wave infrared (MWIR) and long-wave infrared (LWIR) videos demonstrated the efficacy of our proposed approach.展开更多
Laser spectroscopy in the longwave mid-infrared(LWIR)region reveals the structures and properties of various biochemical substances.Here,we demonstrate a broadband LWIR laser covering 5.7-11.0μm with 13 mW average po...Laser spectroscopy in the longwave mid-infrared(LWIR)region reveals the structures and properties of various biochemical substances.Here,we demonstrate a broadband LWIR laser covering 5.7-11.0μm with 13 mW average power and 108 MHz repetition rate based on difference frequency generation(DFG)in a zinc germanium phosphide(ZGP)crystal.The laser can also be widely tuned over 4.6-11.0μm with a maximum average power of 40 mW.The pump and signal pulses of DFG are generated from a broadband optical parametric oscillator(OPO)system pumped by a Yb-doped fiber laser.Absorption spectroscopy of an organic compound was demonstrated by the LWIR source.Furthermore,combining additional complex phase locking,it has the potential to achieve dual comb spectroscopy(DCS)for higher measurement speed and resolution.The adjustment-free LWIR lasers with instantaneous broadband spectra reduce system complexity and alignment difficulty,and they are desirable for sensitive parallel molecular spectroscopy and biological macromolecule detection.展开更多
This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-Ⅱsuperlattices.Utilizing an eight-band k·p Hamilto⁃...This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-Ⅱsuperlattices.Utilizing an eight-band k·p Hamilto⁃nian in conjunction with a scattering matrix method,the model effectively incorporates quantum confinement,strain effects,and interface states.This robust and numerically stable approach achieves exceptional agreement with experimental data,offering a reliable tool for analyzing and engineering the band structure of complex multi⁃layer systems.展开更多
随着碲镉汞(HgCdTe)红外探测器的不断发展,碲镉汞波长已经逐渐从中波向长波/甚长波方向发展,表面效应很大程度上决定了碲镉汞红外焦平面探测器的性能,因此对表面钝化提出了更高的要求。文中通过研究磁控溅射生长的钝化层进行三温段退火...随着碲镉汞(HgCdTe)红外探测器的不断发展,碲镉汞波长已经逐渐从中波向长波/甚长波方向发展,表面效应很大程度上决定了碲镉汞红外焦平面探测器的性能,因此对表面钝化提出了更高的要求。文中通过研究磁控溅射生长的钝化层进行三温段退火改善长波器件性能,实验结果表明低温段(120~170℃)退火显著改善膜层的致密性,二次离子质谱(Secondary ion mass spectroscopy)表明高温段(320℃/2.5 h)退火高组分层厚度达到0.22μm,改善器件的表面漏电流;第三段低温(200~270℃)稳定载流子浓度在1.0×10^(16)~3.0×10^(16) cm^(-3)范围内。三温段退火工艺提高了钝化膜层的致密性、增大了碲镉汞界面的高组分过渡层厚度的同时稳定了碲镉汞材料的电学参数,为长波碲镉汞红外器件的发展奠定了基础。展开更多
介绍了宽视场长波红外(LWIR)光学系统技术指标。离轴三反射镜消像散(TMA)型光学系统光谱覆盖范围宽,可提供一个空间分辨率高、观测范围大的无遮挡视场,能够在 F 数相对较小的光学系统中实现接近衍射极限的光学性能。TMA 型光学系统能满...介绍了宽视场长波红外(LWIR)光学系统技术指标。离轴三反射镜消像散(TMA)型光学系统光谱覆盖范围宽,可提供一个空间分辨率高、观测范围大的无遮挡视场,能够在 F 数相对较小的光学系统中实现接近衍射极限的光学性能。TMA 型光学系统能满足推扫式 LWIR 扫描仪所要求光学系统大观测视场、高光学效率等指标,可作为预先研究星载遥感仪的光学结构。展开更多
文摘为提高长波红外偏振成像系统中偏振器件性能,本文通过分析光栅材料及结构参数对光栅偏振性能的影响,设计并优化了一种双层材料构成的亚波长光栅。该光栅为矩形形貌,光栅区由铝与硒化锌构成,两种材料的厚度分别为0.6μm和0.4μm,光栅周期1μm,占空比50%。利用严格耦合波理论分析并计算该结构光栅的衍射效率,7~15μm波段的光以0~60°入射后其0级横磁模透射率达到87.54%以上,消光比超过47 d B。该光栅在10.6μm的测试波长下,TM透射率高达90.80%且具有50 d B以上的消光比,相比槽深相同的单层铝光栅,偏振透过率明显提高。仿真结果显示,该光栅在整个宽长波红外波段具有良好的偏振性能。
文摘Pixel-wise Code Exposure (PCE) camera is one type of compressive sensing camera that has low power consumption and high compression ratio. Moreover, a PCE camera can control individual pixel exposure time that can enable high dynamic range. Conventional approaches of using PCE camera involve a time consuming and lossy process to reconstruct the original frames and then use those frames for target tracking and classification. In this paper, we present a deep learning approach that directly performs target tracking and classification in the compressive measurement domain without any frame reconstruction. Our approach has two parts: tracking and classification. The tracking has been done using YOLO (You Only Look Once) and the classification is achieved using Residual Network (ResNet). Extensive experiments using mid-wave infrared (MWIR) and long-wave infrared (LWIR) videos demonstrated the efficacy of our proposed approach.
基金National Natural Science Foundation of China(12134004,12274141,62425503,12204178,62105237).
文摘Laser spectroscopy in the longwave mid-infrared(LWIR)region reveals the structures and properties of various biochemical substances.Here,we demonstrate a broadband LWIR laser covering 5.7-11.0μm with 13 mW average power and 108 MHz repetition rate based on difference frequency generation(DFG)in a zinc germanium phosphide(ZGP)crystal.The laser can also be widely tuned over 4.6-11.0μm with a maximum average power of 40 mW.The pump and signal pulses of DFG are generated from a broadband optical parametric oscillator(OPO)system pumped by a Yb-doped fiber laser.Absorption spectroscopy of an organic compound was demonstrated by the LWIR source.Furthermore,combining additional complex phase locking,it has the potential to achieve dual comb spectroscopy(DCS)for higher measurement speed and resolution.The adjustment-free LWIR lasers with instantaneous broadband spectra reduce system complexity and alignment difficulty,and they are desirable for sensitive parallel molecular spectroscopy and biological macromolecule detection.
文摘This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-Ⅱsuperlattices.Utilizing an eight-band k·p Hamilto⁃nian in conjunction with a scattering matrix method,the model effectively incorporates quantum confinement,strain effects,and interface states.This robust and numerically stable approach achieves exceptional agreement with experimental data,offering a reliable tool for analyzing and engineering the band structure of complex multi⁃layer systems.
文摘随着碲镉汞(HgCdTe)红外探测器的不断发展,碲镉汞波长已经逐渐从中波向长波/甚长波方向发展,表面效应很大程度上决定了碲镉汞红外焦平面探测器的性能,因此对表面钝化提出了更高的要求。文中通过研究磁控溅射生长的钝化层进行三温段退火改善长波器件性能,实验结果表明低温段(120~170℃)退火显著改善膜层的致密性,二次离子质谱(Secondary ion mass spectroscopy)表明高温段(320℃/2.5 h)退火高组分层厚度达到0.22μm,改善器件的表面漏电流;第三段低温(200~270℃)稳定载流子浓度在1.0×10^(16)~3.0×10^(16) cm^(-3)范围内。三温段退火工艺提高了钝化膜层的致密性、增大了碲镉汞界面的高组分过渡层厚度的同时稳定了碲镉汞材料的电学参数,为长波碲镉汞红外器件的发展奠定了基础。
