Optical properties of composite materials at high temperatures

Abstract

The optical properties of composite materials are studied theoretically as a function of temperature via a phenomenological model for temperatures up to the melting points of the materials. Both the Maxwell-Garnett and Bruggeman models are considered and the temperature variation of the optical constants of the metallic particles is obtained with an account of the dependence of both the electron-phonon and electron-electron scattering on temperature. The results show that the extinction coefficient of the composite generally increases with temperature and that the Maxwell-Garnett and Bruggeman models can give very different results at certain optical frequency. Transmittance through a thin composite film is calculated providing a means for a simple experimental study of the various modeling results.