Semiconductor nanowire metamaterial for broadband near-unity absorption

TL;DR

This paper presents a novel semiconductor nanowire metamaterial that achieves near-unity broadband infrared absorption at room temperature, enabling advanced sensing and quantum detection applications.

Contribution

The authors design and experimentally demonstrate a semiconductor nanowire metamaterial with near-unity absorption efficiency over a broad infrared range, a significant improvement over existing detectors.

Findings

Achieved 93% measured absorption efficiency from 900 nm to 1500 nm.

Demonstrated collective response from nanowire coupling mechanisms.

Showed potential for room-temperature broadband quantum detectors.

Abstract

The realization of a semiconductor near-unity absorber in the infrared will provide new capabilities to transform applications in sensing, health, imaging, and quantum information science, especially where portability is required. Typically, commercially available portable single-photon detectors in the infrared are made from bulk semiconductors and have efficiencies well below unity. Here, we design a novel semiconductor nanowire metamaterial, and show that by carefully arranging an InGaAs nanowire array and by controlling their shape, we demonstrate near-unity absorption efficiency at room temperature. We experimentally show an average measured efficiency of 93% (simulated average efficiency of 97%) over an unprecedented wavelength range from 900 nm to 1500 nm. We further show that the near-unity absorption results from the collective response of the nanowire metamaterial, originating from both coupling into leaky resonant waveguide and transverse modes. These coupling mechanisms cause light to be absorbed directly from the top and indirectly as light scatters from one nanowire to neighbouring ones. This work leads to the possible development of a new generation of quantum detectors with unprecedented broadband near-unity absorption in the infrared, while operating near room temperature for a wider range of applications.