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

¹ Wave Transport in Complex Systems Lab, Department of Physics, Wesleyan University Middletown, CT 06457, USA
² Department of Physics and Astronomy, University of Texas at San Antonio - San Antonio, TX 78249, USA
³ Air Force Research Laboratory, Sensors Directorate - Wright-Patterson Air Force Base, OH 45433, USA

Received: 23 April 2019
Accepted: 25 June 2019

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.