Abstract

Thermally induced bistability observed experimentally in zinc sulfide and zinc selenide Fabry-Perot etalons¹ has triggered our interest in the dynamic interaction of irradiance, temperature, and the optical properties of interference filters. Linder sufficient power, residual absorption in di electric materials can give rise to internal heating, changing the refractive indices. We have developed a model that considers the time dependence of the coupling between optical property and heat flow equations through the temperature dependence of the optical constants. During each time increment, the internal field inside a multilayer stack is calculated, and the losses in the Poynting vector determine the heat distribution map accordingly. Heat flow equations allow us to derive the corresponding temperature map, the new optical constants of the various materials, and the new values of the optical properties for the next iteration. This simulation follows dynamically the evolution of transmittance, reflectance, and electric field as a function of time, giving temperature and refractive-index maps. Electric-field dependence of the refractive index can also be included to model interference filters involving nonlinear materials.

© 1987 Optical Society of America