Simple phase shifting lateral shearing interferometer based on a thick birefringent plate

A simple phase shifting lateral shearing interferometer based on a thick birefringent plate is proposed. The interferometer is composed of a thick birefringent plate and a polarizer. The thick birefringent plate works as the shear generator as well as the phase shifter. The optical path difference and shearing amount between the two sub-beams emerging from the thick birefringent plate change depending on the incident angle. For incident angles in a certain range, the shearing amount stays almost constant while the optical path difference varies linearly. Thus phase shifting can be obtained by rotating the thick birefringent plate. It is a very simple structure for the testing of a small beam, and equidistant phase shifting can be obtained by equal incident angle variation. The validity of the interferometer is verified by both simulation and experiment. (C) 2017 Optical Society of America