Index matching reduces peak electric fields in thin-film polarizers

Multilayer thin-film polarizers with. and without antireflection layers between the repeating groups of layers and the mediums at both ends of the multilayer are compared for optical electric field levels. It is shown that standing waves can build up the electric fields to higher levels without antireflection layers than with them. Relations are derived between optical throughput and electric field levels for oblique propagation. Numerical values are given for a particular example. A 70% gain in throughput is possible before a given electric field level is reached if antireflection layers are used compared to not using them. Electric fields in the polarizer are compared to those in a V coat. The V coat may handle twice the throughput of the polarizer if the high index material limits allowable levels.