Wavelength‐Linearly‐Dependent and Polarization‐Sensitive Perfect Absorbers based on Optically Anisotropic Germanium Selenide (GeSe)

Abstract Perfect absorbers, widely utilized in solar energy‐harvesting devices, optical communications, sensors, displays, and filters, achieve 100% light absorption. However, perfect absorbers employing micro/nanostructures encounter challenges such as high cost and complexity in simulation and fabrication. Here, novel wavelength‐linearly‐dependent and polarization‐sensitive perfect absorbers utilizing optically anisotropic germanium selenide (GeSe) are proposed. A simple and cost‐effective GeSe‐SiO 2 ‐Si multilayered optical thin film is constructed and optimized to achieve destructive interference, leading to perfect absorption. The operating wavelength can be linearly tuned from 900 nm to 1300 nm by adjusting the GeSe thickness from 125 nm to 200 nm. Leveraging the significant optical anisotropy, the polarization angle is introduced as an additional parameter to dynamically and finely control the operating wavelength, enabling the creation of polarization‐sensitive perfect absorbers. Experimental results validate the feasibility of fabricating and dynamically modulating the proposed wavelength‐linearly‐dependent and polarization‐sensitive perfect absorbers. This study introduces a novel approach for designing and fabricating reconfigurable perfect absorbers utilizing low‐symmetry materials, facilitating mass production and on‐chip integrated systems.