A cube splitter interferometer for phase shifting interferometry and birefringence analysis

Abstract

A cube beam splitter (CBS), which is more often used in two beam interferometers to generate orthogonally directed light beams, can be used to construct a two beam interferometer by aligning its beam-splitting interface parallel to the direction of propagation of light. The monolithic design of the CBS interferometer renders sufficient immunity to ambient vibrations and is worth considering as a convenient arrangement for interferometric testing. The proposed set-up can be used to construct a phase shifting interferometer as well by suitably incorporationg a quarter-wave plate and two polarizers for polarization phase shifting. It is also shown that the CBS interferometer, in a slightly different testing configuration, is birefringence sensitive in the sense that the displacement of the fringes is solely dependent on the birefringence of the sample and not on its surface quality.