Abstract

Starting with the equations of guided waves in a quarterwave multilayer stack (mirror or Fabry-Perot filter), we can calculate the synchronous angles associated with the different TE and TM modes. A comparison to experimental results allows an accurate characterization of the stack. A good approach to this study is to consider the classical case of two alternate materials and, by assuming that layers are rigorously quarterwave, to first determine refractive indices of the two materials. These values can be obtained with good accuracy by a conjoined use of the available TE and TM modes. A more extensive analysis can be made by studying an electric-field distribution for the different modes. In some cases, this can lead to a selective study of some particular layers of the stack. With some examples, we show how this can display anomalies in the stack structure. We find, particularly, that the refractive index of a layer depends on its position in the stack. The influence of the errors on the thicknesses of the layers can be distinguished from those due to index variations.

© 1987 Optical Society of America