Long-wave infrared （IR） generation based on type-Ⅱ （o→e＋o） phase matching ZnGeP2 （ZGP） and CdSe optical parametric oscillators （OPOs） pumped by a 2.05μm Tm,Ho：GdVO4 laser is reported. The comparisons of t...Long-wave infrared （IR） generation based on type-Ⅱ （o→e＋o） phase matching ZnGeP2 （ZGP） and CdSe optical parametric oscillators （OPOs） pumped by a 2.05μm Tm,Ho：GdVO4 laser is reported. The comparisons of the birefringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally. For the ZGP OPO, up to 419 mW output at 8.04 μm is obtained at the 8 kHz pump pulse repetition frequency （PRF） with a slope efficiency of 7.6%. This ZGP OPO can be continuously tuned from 7.8 to 8.5 μm. For the CdSe OPO, we demonstrate a 64 mW output at 8.9μm with a single crystal 28 mm in length.展开更多
In view of the difficulties in traditional long-wave infrared imaging spectrometer which is hard to realize a high signal-to-noise ratio and miniaturization as well under the weak remote sensing signal,Offner convex g...In view of the difficulties in traditional long-wave infrared imaging spectrometer which is hard to realize a high signal-to-noise ratio and miniaturization as well under the weak remote sensing signal,Offner convex grating spectrometer and Dyson concave grating spectrometer,both having concentric structure,are designed and analyzed in the band of 8-12 μm. The diffraction angle expressions of the two spectrometers are obtained and the diffraction characteristics are acquired. Both of the spectrometers are designed in Zemax environment under different F-numbers and different grating constants with the same slit,spatial resolution,spectral resolution and detector. The results show that Dyson grating spectrometer possesses the advantages of higher throughput and smaller volume, and Offner grating spectrometer possesses the advantage of more accessible material and the absence of chromatic aberration. The differences between Dyson form and Offner form show that the former is a better choice in the long-wave infrared imaging spectrometer.展开更多
A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a...A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors.展开更多
The optoelectronic performance of quantum cascade detectors(QCDs)is highly sensitive to the design of the energy level structure,leading to the inability of a single structure to achieve broad wavelength tuning.To add...The optoelectronic performance of quantum cascade detectors(QCDs)is highly sensitive to the design of the energy level structure,leading to the inability of a single structure to achieve broad wavelength tuning.To address this issue,we propose and demonstrate a modular concept for very long wave infrared(VLWIR)QCDs based on a miniband diagonal transition scheme.The modular design makes the wavelength tuning only need to be adjusted for the absorption quantum well module rather than for the whole active region.Theoretical simulation shows that the wavelength tuning range is 39.6 meV(~14–30μm).To prove the feasibility of the scheme,three samples with different absorption well widths were fabricated and characterized.At 10 K,the response wavelengths of the three QCDs are 14,16,and 18μm,respectively,corresponding to responsivities and detectivities exceeding 2 mA/W and 1×10^(10)Jones.展开更多
Metasurfaces in the long wave infrared(LWIR)spectrum hold great potential for applications in ther-mal imaging,atmospheric remote sensing,and target identification,among others.In this study,we designed and experiment...Metasurfaces in the long wave infrared(LWIR)spectrum hold great potential for applications in ther-mal imaging,atmospheric remote sensing,and target identification,among others.In this study,we designed and experimentally demonstrated a 4 mm size,all-silicon metasurface metalens with large depth of focus opera-tional across a broadband range from 9µm to 11.5µm.The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region,thus paving the way for practical LWIR applications of met-alens technology.展开更多
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
We introduce a novel method to create mid-infrared(MIR)thermal emitters using fully epitaxial,metal-free structures.Through the strategic use of epsilon-near-zero(ENZ)thin films in InAs layers,we achieve a narrow-band...We introduce a novel method to create mid-infrared(MIR)thermal emitters using fully epitaxial,metal-free structures.Through the strategic use of epsilon-near-zero(ENZ)thin films in InAs layers,we achieve a narrow-band,wide-angle,and p-polarized thermal emission spectra.This approach,employing molecular beam epitaxy,circumvents the complexities associated with current layered structures and yields temperature-resistant emission wavelengths.Our findings contribute a promising route towards simpler,more efficient MIR optoelectronic devices.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60878011 and 61078008)the Program for New Century Excellent Talents in University,China (Grant No. NCET-10-0067)
文摘Long-wave infrared （IR） generation based on type-Ⅱ （o→e＋o） phase matching ZnGeP2 （ZGP） and CdSe optical parametric oscillators （OPOs） pumped by a 2.05μm Tm,Ho：GdVO4 laser is reported. The comparisons of the birefringent walk-off effect and the oscillation threshold between ZGP and CdSe OPOs are performed theoretically and experimentally. For the ZGP OPO, up to 419 mW output at 8.04 μm is obtained at the 8 kHz pump pulse repetition frequency （PRF） with a slope efficiency of 7.6%. This ZGP OPO can be continuously tuned from 7.8 to 8.5 μm. For the CdSe OPO, we demonstrate a 64 mW output at 8.9μm with a single crystal 28 mm in length.
基金Sponsored by the National High Technology Research and Development Program of China(863 Program)(Grant No.2013AA03A116)
文摘In view of the difficulties in traditional long-wave infrared imaging spectrometer which is hard to realize a high signal-to-noise ratio and miniaturization as well under the weak remote sensing signal,Offner convex grating spectrometer and Dyson concave grating spectrometer,both having concentric structure,are designed and analyzed in the band of 8-12 μm. The diffraction angle expressions of the two spectrometers are obtained and the diffraction characteristics are acquired. Both of the spectrometers are designed in Zemax environment under different F-numbers and different grating constants with the same slit,spatial resolution,spectral resolution and detector. The results show that Dyson grating spectrometer possesses the advantages of higher throughput and smaller volume, and Offner grating spectrometer possesses the advantage of more accessible material and the absence of chromatic aberration. The differences between Dyson form and Offner form show that the former is a better choice in the long-wave infrared imaging spectrometer.
文摘A ten-month field research study was meticulously conducted at Robert Moses State Park (RMSP) on the south shore of Long Island, NY. The objective was to determine if aerial phenomena of an unknown nature exist over a coastal location and to characterize their properties and behaviors. Primary and secondary field observation methods were utilized in this data-centric study. Forensic engineering principles and methodologies guided the study. The challenges set forward were object detection, observation, and characterization, where multispectral electro-optical devices and radar were employed due to limited visual acuity and intermittent presentation of the phenomena. The primary means of detection utilized a 3 cm X-band radar operating in two scan geometries, the X- and Y-axis. Multispectral electro-optical devices were utilized as a secondary means of detection and identification. Data was emphasized using HF and LF detectors and spectrum analyzers incorporating EM, ultrasonic, magnetic, and RF field transducers to record spectral data in these domains. Data collection concentrated on characterizing VIS, NIR, SWIR, LWIR, UVA, UVB, UVC, and the higher energy spectral range of ionizing radiation (alpha, beta, gamma, and X-ray) recorded by Geiger-Müller counters as well as special purpose semiconductor diode sensors.
基金supported by the National Natural Science Foundation of China(Nos.61835011,62335015,12393830,62222408,and 12274404)the Key Program of the Chinese Academy of Sciences(No.XDB43000000)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022112)。
文摘The optoelectronic performance of quantum cascade detectors(QCDs)is highly sensitive to the design of the energy level structure,leading to the inability of a single structure to achieve broad wavelength tuning.To address this issue,we propose and demonstrate a modular concept for very long wave infrared(VLWIR)QCDs based on a miniband diagonal transition scheme.The modular design makes the wavelength tuning only need to be adjusted for the absorption quantum well module rather than for the whole active region.Theoretical simulation shows that the wavelength tuning range is 39.6 meV(~14–30μm).To prove the feasibility of the scheme,three samples with different absorption well widths were fabricated and characterized.At 10 K,the response wavelengths of the three QCDs are 14,16,and 18μm,respectively,corresponding to responsivities and detectivities exceeding 2 mA/W and 1×10^(10)Jones.
基金Supported by National Key R&D Program of China(2021YFA0715500)National Natural Science Foundation of China(NSFC)(12227901)+1 种基金Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB0580000)Chinese Academy of Sciences President's In-ternational Fellowship Initiative(2021PT0007).
文摘Metasurfaces in the long wave infrared(LWIR)spectrum hold great potential for applications in ther-mal imaging,atmospheric remote sensing,and target identification,among others.In this study,we designed and experimentally demonstrated a 4 mm size,all-silicon metasurface metalens with large depth of focus opera-tional across a broadband range from 9µm to 11.5µm.The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region,thus paving the way for practical LWIR applications of met-alens technology.
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We introduce a novel method to create mid-infrared(MIR)thermal emitters using fully epitaxial,metal-free structures.Through the strategic use of epsilon-near-zero(ENZ)thin films in InAs layers,we achieve a narrow-band,wide-angle,and p-polarized thermal emission spectra.This approach,employing molecular beam epitaxy,circumvents the complexities associated with current layered structures and yields temperature-resistant emission wavelengths.Our findings contribute a promising route towards simpler,more efficient MIR optoelectronic devices.
