High-Performance Ultra-Broadband Absorber for Polarized Long-Wavelength Infrared Light Trapping

Abstract

Conventional infrared polarization imaging and detection systems are normally complex, bulky, and expensive, since rare existing absorber components possess polarization selectivity, especially in the long-wavelength infrared (LWIR) range. In this study, we propose a novel high-performance metamaterial absorber with ultra-broadband high absorption and polarization selectivity in the entire LWIR atmospheric window. The absorber can realize an absorptance higher than 90% with a 4750 nm bandwidth due to different surface plasmons coupled with optical phonons. It exhibits precise polarization-selective absorption at the target wavelength; specifically, it can selectively trap TM-polarized light while restricting the absorption of TE-polarized light. In addition, the designed metamaterial exhibits remarkable spectral stability when the geometric parameters of the microstructure change, which is of great benefit in its manufacturing process. The proposed ultra-thin absorber provides a promising approach to simplify LWIR imaging and detection systems and further improve their performance.