Ultra-broadband Light Absorption by a Sawtooth Anisotropic Metamaterial Slab

TL;DR

This paper introduces an ultra-broadband infrared absorber using a sawtooth-shaped anisotropic metamaterial slab, achieving over 95% absorption across a wide frequency range and angles, with potential applications in photovoltaics and thermal emitters.

Contribution

The study demonstrates a novel sawtooth anisotropic metamaterial design for ultra-broadband light absorption with high efficiency and angle insensitivity.

Findings

Achieves over 95% absorptivity across a broad frequency range.

Maintains high absorption at various incident angles.

Utilizes slow-light modes for wavelength-specific light trapping.

Abstract

We present an ultra broadband thin-film infrared absorber made of saw-toothed anisotropic metamaterial. Absorbtivity of higher than 95% at normal incidence is supported in a wide range of frequencies, where the full absorption width at half maximum is about 86%. Such property is retained well at a very wide range of incident angles too. Light of shorter wavelengths are harvested at upper parts of the sawteeth of smaller widths, while light of longer wavelengths are trapped at lower parts of larger tooth widths. This phenomenon is explained by the slowlight modes in anisotropic metamaterial waveguide. Our study can be applied in the field of designing photovoltaic devices and thermal emitters.