MULTILAYER-COATED OPTICS - GUIDED-WAVE COUPLING AND SCATTERING BY MEANS OF INTERFACE RANDOM ROUGHNESS

For plane-wave light incident upon multilayer optical components, we u se first-order perturbation theory to calculate two effects of interfa ce roughness: (1) angle-resolved scattering and (2) guided-made coupli ng. The interface roughness, which is assumed to be a random variable having root-mean-square roughness much less than the incident waveleng th, is the perturbation parameter. When guided-wave mode resonances ar e inherent in optical component design, we show that fractions of inci dent energy scattered directly and coupled into guided-wave modes are comparable. It follows that, in consideration of multilayer optics, en ergy coupled into guided-wave modes can be an equally important consid eration, as this energy may then end up as an additional contribution to scattering and absorption.