A Laser Polarimetric Sensor for Measuring Angular Displacements of Objects

Abstract

One of the promising applications of laser autocollimating polarimetric sensors is measuring angular displacements of objects. For this purpose a parallel-sided plate, cut out of a birefringent crystal, and a retroreflector are mounted onto the object. The collimating beam of the polarimeter is sighted at the object and reflected back by the retroreflector. By this the beam pass two times through the birefringent plate. Retardance, caused by the plate in the beam, is proportionate to plate's tilt. Having measured the returdance by means of the polarimeter one can define the angle of the object's tilt [1].