A new scheme for phase-shifting ESPI using polarized light

A new scheme for achieving electronic speckle pattern interferometry (ESPI) is presented, in which two polarizing cube beam splitters placed together are used to achieve the superposition of orthogonal polarized light waves coming from the reference and the test object, respectively. Polarization phase stepping occurs by changing the so-called Pancharatnam's phase by means of the rotation of a polarizer situated in front of a digital camera. Experiments were carried out to show the feasibility of the system. A compact system that uses a micropolarizer camera for achieving instantaneous ESPI is also proposed.