Wide band gap phase change material tuned visible photonics

TL;DR

This paper demonstrates the use of the tunable band gap phase change material Sb2S3 in visible photonics, enabling reversible optical modulation in the visible spectrum for high-speed reprogrammable devices.

Contribution

It introduces Sb2S3 as a low-absorption, tunable band gap phase change material for visible light applications, coupling it with optical resonators for dynamic control.

Findings

Sb2S3's band gap can be tuned from 2.0 to 1.7 eV.

Reversible optical responses are achieved via structural phase transitions.

Devices can be triggered optically and electrically.

Abstract

Light strongly interacts with structures that are of a similar scale to its wavelength; typically nanoscale features for light in the visible spectrum. However, the optical response of these nanostructures is usually fixed during the fabrication. Phase change materials offer a way to tune the properties of these structures in nanoseconds. Until now, phase change active photonics use materials that strongly absorb visible light, which limits their application in the visible spectrum. In contrast, Stibnite (Sb2S3) is an under-explored phase change material with a band gap that can be tuned in the visible spectrum from 2.0 to 1.7 eV. We deliberately couple this tuneable band gap to an optical resonator such that it responds dramatically in the visible spectrum to Sb2S3 reversible structural phase transitions. We show that this optical response can be triggered both optically and electrically. High speed reprogrammable Sb2S3 based photonic devices, such as those reported here, are likely to have wide applications in future intelligent photonic systems, holographic displays, and micro-spectrometers.