Grating Structure Broadband Absorber Based on Gallium Arsenide and Titanium

Abstract

We designed a broadband absorber based on a multilayer grating structure composed of gallium arsenide and titanium. The basic unit is a grating structure stacked on top of a semiconductor of gallium arsenide and titanium metal. We used the finite difference time domain method to simulate the designed model and found that the absorber absorption efficiency exceeded 90% in the range from 736 nm to 3171 nm. The absorption efficiency near perfect absorption at 867 nm was 99.69%. The structure had good angle insensitivity, and could maintain good absorption under both the TE mode and TM mode polarized light when the incident angle of the light source changed from 0° to 50°. This kind of metamaterial grating perfect absorber is expected to be widely used in optical fields such as infrared detection, optical sensing, and thermal electronics.