Properties of Weakly Absorbing Multilayer Systems in Terms of the Concept of Potential Transmittance

The general expression for the potential transmittance of a layer, first derived by Berning and Turner [1], is simplified by the use of approximations applicable to weakly absorbing layers, and then used to describe the optical performance of mirrors and narrow-band filters consisting of such layers. In particular, simple expressions are obtained for the transmittance and absorptance of all-dielectric filters in terms of the width of their passband. These provide useful guides to the design of filters with minimum reduction of transmittance due to absorption in the layers, and also allow the absorptance and scattering contributions to be separated in measurements of the total loss.