Beam-splitter Coatings for Producing Phase Quadrature Interferometer Outputs

Abstract

The measurement of displacement using a Michelson-type interferometer requires a beam-splitter coating that ideally produces two signals in phase quadrature. In this paper a number of beam-splitter designs utilizing thin metal films are discussed. Problems associated with film deposition and monitoring are considered, and it is shown that, using conventional techniques, the required phase difference can be readily achieved using, for example, combinations of gold, chromium and aluminium films.