Sensitive devices to determine the state and degree of polarization of a light beam using a birefringence modulator

Abstract

A number of physical phenomena are known to modify the state of polarization of a light beam. Different devices are described including the use of a polarization modulator, a photoelastic one for instance. These devices allow the determination of dichroism, the degree of polarization of a light beam or features of elliptical light (ellipticity, azimuth of the axis of the ellipse). The performance of the various devices is evaluated in terms of the signal/noise ratio (s/n) when the fundamental noise is the shot noise of a phototube (UV-vis. range) or the noise inherent to the detector (IR range).