Brewster's angle thin film plate polarizer design study from an electric field perspective

The electric field magnitude and profile influence the laser-induced damage threshold and morphology of a multilayer coating. Through the use of non-quarter-wave layer pairs in high reflector designs, the electric field peaks are shifted into the low index layers thus reducing the electic fields in the high index layers and interfaces. Similarly the electric field profile in a polarizer can be optimized for low electric fields within the high index layers and film interfaces by proper design selection. The traditional approach to Brewster's angle thin film polarizer design starts with a long-wave pass design to exploit the angle-induced differential high reflection bandwidths for "P" and "S" polarization. The design is optimized to admittance match the exterior and interior layers of the central stack to the surrounding media (air and glass). This design yields a broad polarizing region with electric field peaks within the high index layers. If a short-wave pass design is optimized, a narrower bandwidth polarizing region is realized with a slightly thicker coating, but the electric field peaks are now shifted to the low index material. In this paper, different starting designs are examined including short-wave pass, long-wave pass, and Fabry-Perot bandpass for electric field profile, polarizing region bandwidth, sensitivity to layer thickness errors, total thickness, and extinction ratio.