The theoretical investigation of the coupling efficiency of a laser diode to a single mode fiber via a hemispherical lens on the tip of the tapered fiber in the presence of possible transverse offset and angular misma...The theoretical investigation of the coupling efficiency of a laser diode to a single mode fiber via a hemispherical lens on the tip of the tapered fiber in the presence of possible transverse offset and angular mismatch is reported.Without the misalignment,coupling efficiency increases with the decreasing of taper length.With the misalignment,this relation is that the coupling efficiency decreases with each kind of offset.展开更多
Light polarization could provide critical visual information(e.g., surface roughness, geometry, or orientation) of the imaged objects beyond prevailing signals of intensity and wavelength. The polarization imaging tec...Light polarization could provide critical visual information(e.g., surface roughness, geometry, or orientation) of the imaged objects beyond prevailing signals of intensity and wavelength. The polarization imaging technology thus has a large potential in broad fields such as object detection. However, intricate polarization coding is often required in these fields, and the existing complicated lensed system and polarizers have limited the miniaturization capabilities of the integrated imaging sensor. In this study, we demonstrate the utilization of two-dimensional(2 D) in-plane anisotropic α-Ge Se semiconductor to realize the polarizer-free polarization-sensitive visible/near-infrared(VIS-NIR) photodetector/imager. As the key part of the sensor system, this prototype Au/Ge Se/Au photodetector exhibits impressive performances in terms of high sensitivity, broad spectral response, and fast-speed operation(~10^(3) A W^(-1), 400–1050 nm,and 22.7/49.5 μs). Further, this device demonstrates unique polarization sensitivity in the spectral range of 690–1050 nm and broadband absorption of light polarized preferentially in the y-direction, as predicted by the analysis of optical transition behavior in α-Ge Se. Then we have successfully incorporated the 2 D Ge Se device into an imaging system for the polarization imaging and captured the polarization information of the radiant target with a high contrast ratio of 3.45 at808 nm(NIR band). This proposed imager reveals the ability to sense dual-band polarization signals in the scene withoutpolarizers and paves the way for polarimetric imaging sensor arrays for advanced applications.展开更多
文摘The theoretical investigation of the coupling efficiency of a laser diode to a single mode fiber via a hemispherical lens on the tip of the tapered fiber in the presence of possible transverse offset and angular mismatch is reported.Without the misalignment,coupling efficiency increases with the decreasing of taper length.With the misalignment,this relation is that the coupling efficiency decreases with each kind of offset.
基金supported by the National Natural Science Foundation of China (61622406,61904015,11674310,61725505 and 11734016)the National Key Research and Development Program of China (2017YFA0207500)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (XDB30000000)the “The Pearl River Talent Recruitment Program”(2019ZT08X639)Beijing National Laboratory for Molecular Sciences (BNLMS201908)。
文摘Light polarization could provide critical visual information(e.g., surface roughness, geometry, or orientation) of the imaged objects beyond prevailing signals of intensity and wavelength. The polarization imaging technology thus has a large potential in broad fields such as object detection. However, intricate polarization coding is often required in these fields, and the existing complicated lensed system and polarizers have limited the miniaturization capabilities of the integrated imaging sensor. In this study, we demonstrate the utilization of two-dimensional(2 D) in-plane anisotropic α-Ge Se semiconductor to realize the polarizer-free polarization-sensitive visible/near-infrared(VIS-NIR) photodetector/imager. As the key part of the sensor system, this prototype Au/Ge Se/Au photodetector exhibits impressive performances in terms of high sensitivity, broad spectral response, and fast-speed operation(~10^(3) A W^(-1), 400–1050 nm,and 22.7/49.5 μs). Further, this device demonstrates unique polarization sensitivity in the spectral range of 690–1050 nm and broadband absorption of light polarized preferentially in the y-direction, as predicted by the analysis of optical transition behavior in α-Ge Se. Then we have successfully incorporated the 2 D Ge Se device into an imaging system for the polarization imaging and captured the polarization information of the radiant target with a high contrast ratio of 3.45 at808 nm(NIR band). This proposed imager reveals the ability to sense dual-band polarization signals in the scene withoutpolarizers and paves the way for polarimetric imaging sensor arrays for advanced applications.
