Thin Film Thermochromic Materials for Non-Linear Optical Devices.

Abstract

AbstractA number of materials are available which exhibit thermochromic properties. These include the superionic materials (eg silver sulphide), phase transition materials (eg vanadium dioxide) and mixed valence materials (eg SmS). Such materials can be exploited as optical thin films and when incorporated into multilayer structures exhibit non-linear properties, particularly at wavelengths in the infra-red (1–12μm). The response of such devices is dependant on the degree of temperature rise produced in the active material, which in turn is dependant on the optical properties of the material and the heat sinking characteristics of the substrate. A summary is presented highlighting techniques for film deposition, multilayer device design and temporal response characteristics measured under conditions of pulsed irradiation.