Ultra-wideband THz/IR Metamaterial Absorber based on Doped Silicon

TL;DR

This paper introduces a doped silicon-based all-dielectric metamaterial absorber that achieves over 95% broadband absorption from 0.6 to 10 THz, suitable for various technological applications.

Contribution

It presents a novel all-dielectric THz absorber design with broad bandwidth, polarization insensitivity, and wide incident angle operation, validated by both simulations and experiments.

Findings

Achieves >95% absorption from 0.6 to 10 THz

Operates across THz to mid-infrared range

Demonstrates polarization insensitivity and wide-angle performance

Abstract

Metamaterial-based absorbers have been extensively investigated in the terahertz (THz) range with ever increasing performances. In this paper, we propose an all-dielectric THz absorber based on doped silicon. The unit cell consists of a silicon cross resonator with an internal cross-shaped air cavity. Numerical results suggest that the proposed absorber can operate from THz to mid-infrared, having an average power absorption of >95% between 0.6 and 10 THz. Experimental results using THz time-domain spectroscopy show a good agreement with simulations. The underlying mechanisms for broadband absorptions are attributed to the combined effects of multiple cavities modes formed by silicon resonators and bulk absorption in the substrate, as confirmed by simulated field patterns. This ultra-wideband absorption is polarization insensitive and can operate across a wide range of the incident angle. The proposed absorber can be readily integrated into silicon-based platforms and is expected to be used in sensing, imaging, energy harvesting and wireless communications systems.