A Polarization Interferometer for Density Measurements in Compressible Flow

Abstract

Polarization interferometry is an optical technique utilizing birefringent devices in conjunction with polarizers to generate interferograms which lend themselves readily to quantitative analysis. The need for two physically distinct light beams as used in the classical Mach-Zehnder interferometer is eliminated, making a much simpler optical arrangement possible. The ease of application of the technique, together with the low cost of the component parts, means that the polarization interferometer can be used to advantage in preference to the classical interferometer in all cases except those where extreme accuracy is the overriding criterion.