An all-transparent symmetric trilayer structure, which consists of a high-index center layer coated on both sides by a low-index film and embedded in a high-index prism, can function as an efficient polarizer or polarizing beam splitter under conditions of frustrated total internal reflection over a wide range of incidence angles. For a given set of refractive indices, all possible solutions for the thicknesses of the layers that suppress the reflection of either the p or s polarization at a specified angle, as well as the reflectance of the system for the orthogonal polarization, are determined. A 633 nm design that uses a MgF2-ZnS-MgF2 trilayer embedded in a ZnS prism achieves an extinction ratio (ER)>40 dB from 50° to 80° in reflection and an ER>20 dB from 58° to 80° in transmission. IR polarizers that use CaF2-Ge-CaF2 trilayers embedded in a ZnS prism are also considered.
Rasheed M. A. Azzam and Siva R. Perla, "Polarizing properties of embedded symmetric trilayer stacks under conditions of frustrated total internal reflection," Appl. Opt. 45, 1650-1656 (2006)