基于各向异性二维Ge Se的无偏振器偏振图像传感器

偏振是光的一个重要信息,偏振探测可以把信息量从三维(光强、光谱和空间)扩充到七维(光强、光谱、空间、偏振度、光偏振等),为成像物体提供关键的视觉信息(如表面粗糙度、几何形状或方向),因此偏振成像技术在目标检测等领域有着巨大的潜力.然而这些领域往往需要复杂的偏振编码,现有的复杂透镜系统和偏振器限制了集成成像传感器的小型化能力.本文通过二维各向异性α-Ge Se半导体,成功实现了无偏振器的偏振敏感可见-近红外光电探测器/成像仪.作为传感器系统的关键部件,该原型Au/GeSe/Au光电探测器具有灵敏度高、光谱响应宽、响应速度快(~10³A W^-1, 400–1050 nm, 22.7/49.5μs)等优点.此外,该器件在690–1050 nm光谱范围内表现出独特的偏振灵敏度,并且对沿y方向的偏振光吸收最强,这一点通过分析α-Ge Se的光跃迁行为也得到了证实.最后,将2D-Ge Se器件应用到成像系统中进行偏振成像,在808 nm近红外波段处,在不同的偏振方向上,辐射目标的对比度为3.45.这种成像仪在没有偏振器的情况下,能够在场景中感知双频偏振信号,为偏振成像传感器阵列的广泛应用奠定了基础.

Polarizer-free polarimetric image sensor through anisotropic two-dimensional Ge Se

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(~10³ 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.