Ultrahigh Extinction Ratio Long‐Wave Infrared Polarization‐Selective Broadband Metamaterial Absorber

Abstract

Metamaterial absorbers (MAs) provide new miniaturization, integration, and high‐performance solution for infrared polarization imaging systems. However, it is challenging for past MAs to obtain broadband absorption and a high extinction ratio simultaneously. Herein, a long‐wave infrared broadband polarization‐selective MA with an ultrahigh extinction ratio is proposes and numerically demonstrated. The MA is composed of a metal–dielectric–metal sandwich structure. The cut‐wire resonator on the top layer and the wire pair on the bottom layer provide the MA with excellent polarization selectivity. In the wavelength range of 8.28–14.15 μm, the absorption of the Transverse Magnetic (TM) wave is greater than 90%, while the absorption of the Transverse Electric (TE) wave is less than 0.15%, and the average extinction ratio reaches 724. The high extinction ratio remains to reach 119 when the MA is integrated into a silicon substrate. This work promises to bring new solutions to infrared polarization imaging.