Loss mechanisms in dielectric optical interference devices

Residual absorption and scattering are loss mechanisms that degrade the performance of all thin films optical devices. By analogy to residual absorption, expressions are derived to evaluate losses due to surface and bulk scattering in dielectric multilayers. Based on these, proposals are made to improve the traditional performances of some basic filters. It is shown how, by means of index inhomogeneity, surface scattering is expected to be reduced considerably.