# Light-induced optical switching in an asymmetric metal-dielectric microcavity with phase-change material

## TL;DR

This paper introduces an infrared optical switch using an asymmetric microcavity with a phase-change material, enabling light-controlled switching between high transmission and reflection states.

## Contribution

It presents a novel microcavity design that leverages phase-change material heating to achieve efficient, binary optical switching at infrared frequencies.

## Key findings

- High resonant transmittance in low-temperature phase
- Abrupt change to high reflectivity upon phase transition
- Broad frequency range operation

## Abstract

We propose an infrared power switch based on an asymmetric high-Q microcavity incorporating a metallic nanolayer in close proximity to a layer made of a phase-change material (PCM). The microcavity is designed so that when the PCM layer is in the low-temperature phase, the metallic nanolayer coincides with a nodal plane of the resonant electric field component, to allow a high resonant transmittance. As the light intensity exceeds a certain threshold, light-induced heating of the PCM layer triggers the phase transition accompanied by an abrupt change in its refractive index in the vicinity of the transition temperature. The latter results in a shift of the nodal plane away from the metallic nanolayer, rendering the entire microcavity highly reflective over a broad frequency range. The nearly binary nature of the PCM refractive index allows for the low-intensity resonant transmission over a broad range of ambient temperatures below the transition point.