Polarization phase-shifting interferometer by rotating azo-polymer film with photo-induced optical anisotropy

• A new interferometer is presented utilizing a rotated azo film with anisotropy.
• The interferograms are theoretically analyzed using Jones matrix calculations.
• Experimental verification shows the effectiveness of the interferometer.
• Birefringence of the azo film is measured using a photoelastic modulator.
• A new application of azo film in phase-shifting interferometer is demonstrated.

A new type of phase-shifting interferometer was presented by rotating an azo-polymer film with photo-induced optical anisotropy in the light path of orthogonal polarization interferometry. By changing the angle of the optical axis of the azo-polymer film, four phase-shifted fringe patterns were obtained, from which phase difference between orthogonal polarized light could be calculated. The polarization states and the formation of the interferograms were analyzed theoretically using Jones matrix calculations and the experimental verification of the proposed method was also given. This method has a simple optical configuration which utilizes commercially available polarization devices and anisotropic azo-polymer film of low cost. The phase-shifting interferometer also demonstrates a new application of azo-polymer film.