Polarization-dependent broadband absorber based on composite metamaterials in the long-wavelength infrared range

Capturing polarization information has long been an important topic in the field of detection. In this study, two polarization-dependent broadband absorbers based on a composite metamaterial structure were designed and numerically investigated. Unlike in conventional metamaterial absorbers, the bottom metallic film is functionalized to achieve a polarization response or broadband absorption. The simulation results show that the type I absorber exhibits TM polarization-dependent broadband absorption (absorptivity>80%) from 8.37 mu m to 12.12 mu m. In contrast, the type II absorber presents TE polarization-dependent broadband absorption (absorptivity>80%) from 8.23 mu m to 11.93 mu m. These devices are extremely sensitive to the change of polarization angle. The absorptivity changes monotonically with an increase of the polarization angle, but it is insensitive to oblique incidence. This design paves the way for realizing broadband polarization-dependent absorption via a simple configuration. It has bright prospects in thermal detection applications and imaging fields. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Two polarization-dependent broadband absorbers based on a composite metamaterial structure were designed and investigated, showing sensitivity to changes in polarization angle and monotonically varying absorptivity with an increase in polarization angle. This design paves the way for broadband polarization-dependent absorption with bright prospects in thermal detection applications and imaging fields.