Large-area, wide-angle, spectrally selective plasmonic absorber

TL;DR

This paper presents a low-cost, large-area metamaterial-based infrared absorber with wide-angle and spectrally selective properties, achieving up to 95% absorption, controlled by metamaterial dimensions, suitable for infrared pixel applications.

Contribution

It introduces a simple, scalable fabrication method for wide-angle, spectrally selective plasmonic absorbers with theoretical and experimental validation.

Findings

Achieves up to 95% infrared absorption.

Absorption peak controlled by metamaterial dimensions.

Maintains perfect absorption over wide angles.

Abstract

A simple metamaterial-based wide-angle plasmonic absorber is introduced, fabricated, and experimentally characterized using angle-resolved infrared spectroscopy. The metamaterials are prepared by nano-imprint lithography, an attractive low-cost technology for making large-area samples. The matching of the metamaterial's impedance to that of vacuum is responsible for the observed spectrally selective "perfect" absorption of infrared light. The impedance is theoretically calculated in the single-resonance approximation, and the responsible resonance is identified as a short-range surface plasmon. The spectral position of the absorption peak (which is as high as 95%) is experimentally shown to be controlled by the metamaterial's dimensions. The persistence of "perfect" absorption with variable metamaterial parameters is theoretically explained. The wide-angle nature of the absorber can be utilized for sub-diffraction-scale infrared pixels exhibiting spectrally selective absorption/emissivity.