Ultra-broad band perfect absorption realized by phonon-photon resonance in periodic polar dielectric material based pyramid structure

TL;DR

This paper demonstrates a mid-infrared ultra-broadband perfect absorber using a pyramid grating structure in SiC, achieving wide-angle, polarization-insensitive absorption through phonon-photon resonance, with potential sensor applications.

Contribution

It introduces a novel pyramid grating design for broadband perfect absorption in the mid-infrared, explaining the mechanism via PLC circuit model and demonstrating omnidirectional, polarization-insensitive performance.

Findings

Achieved perfect absorption between 10.25 and 10.85 μm.

Modified geometry to connect discrete peaks into a continuous band.

Demonstrated angle and polarization insensitivity in simulations.

Abstract

In this research, a mid-infrared wide-angle ultra-broadband perfect absorber which composed of pyramid grating structure has been comprehensively studied. The structure was operated in the reststrahlem band of SiC and with the presence of surface phonon resonance(SPhR), the perfect absorption was observed in the region between 10.25 and 10.85 $\mu m$. We explain the mechanism of this structure with the help of PLC circuit model due to the independence of magnetic polaritons. More over, by studying the resonance behavior of different wavelength, we bridged the continuous perfect absorption band and the discret peak in 11.05 $\mu m$(emerge two close absorption band together) by modification of the geometry. The absorption band has been sufficiently broadened. More over, both 1-D and 2-D periodic structure has been considered and the response of different incident angles and polarized angles have been studied and a omnidirectional and polarization insensitive structure can be realized which may be a candidate of several sensor applications in meteorology. The simulation was conducted by the Rigorous Coupled Wave Method(RCWA).