Polarization phase-shifting Fizeau interferometer with a cyclic path optical configuration

TLDR: In this article, a cyclic path optical configuration was used to generate coherent, virtual point sources at the back focal plane of a corrected telescope objective for producing a pair of mutually tilted collimated beams with linear orthogonal polarizations in a Fizeau interferometer cavity.

Abstract: A new technique, using a cyclic path optical configuration, for generating two coherent, virtual point sources at the back focal plane of a corrected telescope objective, for producing a pair of mutually tilted collimated beams with linear orthogonal polarizations in a Fizeau interferometer cavity is presented. The orthogonal linear polarization components reflected from the reference and the test surfaces are utilized for introducing polarization phase shift between the reference and test waves. A method for elimination of the residual instrumental aberration due to a slight departure from strict on-axis operation is discussed. The result for a plane optical surface is presented. Because, in polarization phase shifting, it is possible to capture all the necessary phase-shifted interferograms simultaneously, the vibration susceptibility can be minimized and the present system could be applied for dynamic interferometry.