As a new member of 2D materials, GeSe has attracted considerable attention recently due to its fascinating in‐plane anisotropic vibrational, electrical, and optical properties originating from the low‐symmetry crystal structure. Among these anisotropic properties, the anisotropic optical property, as a new degree of freedom to manipulate optoelectronic properties in 2D materials, is of great importance for practical applications. However, the fundamental understanding of the optical anisotropy of GeSe is still under exploration, severely restricting its utility in polarization‐sensitive optical systems. Here, a systematic study about the in‐plane optical anisotropy of GeSe is reported, including its anisotropic optical absorption, reflection, extinction, and refraction. The anisotropic band structure of GeSe is experimentally observed for the first time through angle‐resolved photoemission spectroscopy, explaining the origin of the optical anisotropy. The anisotropic reflection and refraction of GeSe are further directly visualized through the angle‐dependent optical contrast of GeSe flakes by azimuth‐dependent reflectance difference microscopy and polarization‐resolved optical microscopy, respectively. Finally, GeSe‐based photodetectors exhibit a polarization‐sensitive photoresponsivity due to the intrinsic linear dichroism. This study provides fundamental information for the optical anisotropy of GeSe, forcefully stimulating the exploration of novel GeSe‐based optical and optoelectronic applications.

中文翻译：

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低对称二维GeSe的面内光学各向异性

作为2D材料的新成员，GeSe由于其低对称性晶体结构引人入胜的面内各向异性振动，电学和光学特性，最近引起了相当大的关注。在这些各向异性性质中，各向异性光学性质作为操纵2D材料中光电性质的新自由度，对实际应用非常重要。然而，对GeSe光学各向异性的基本理解仍在探索中，严重限制了其在偏振敏感光学系统中的应用。在此，对GeSe的面内光学各向异性进行了系统的研究，包括其各向异性的光学吸收，反射，消光和折射。通过角度分辨光发射光谱法首次实验观察到了GeSe的各向异性能带结构，从而解释了光学各向异性的起源。分别通过方位角相关的反射率差显微镜和偏振分辨光学显微镜，分别通过GeSe片的角度相关的光学对比，进一步直观地观察到GeSe的各向异性反射和折射。最后，由于固有的线性二向色性，基于GeSe的光电探测器表现出对偏振敏感的光响应性。这项研究为GeSe的光学各向异性提供了基础信息，有力地刺激了基于GeSe的新型光学和光电应用的探索。分别通过方位角相关的反射率差显微镜和偏振分辨光学显微镜，分别通过GeSe片的角度相关的光学对比，进一步直观地观察到GeSe的各向异性反射和折射。最后，由于固有的线性二向色性，基于GeSe的光电探测器表现出对偏振敏感的光响应性。这项研究为GeSe的光学各向异性提供了基础信息，有力地刺激了基于GeSe的新型光学和光电应用的探索。分别通过方位角相关的反射率差显微镜和偏振分辨光学显微镜，分别通过GeSe片的角度相关的光学对比，进一步直观地观察到GeSe的各向异性反射和折射。最后，由于固有的线性二向色性，基于GeSe的光电探测器表现出对偏振敏感的光响应性。这项研究为GeSe的光学各向异性提供了基础信息，有力地刺激了基于GeSe的新型光学和光电应用的探索。由于固有的线性二向色性，基于GeSe的光电探测器表现出对偏振敏感的光响应性。这项研究为GeSe的光学各向异性提供了基础信息，有力地刺激了基于GeSe的新型光学和光电应用的探索。由于固有的线性二向色性，基于GeSe的光电探测器表现出对偏振敏感的光响应性。这项研究为GeSe的光学各向异性提供了基础信息，有力地刺激了基于GeSe的新型光学和光电应用的探索。