Instantaneous phase-shifting Fizeau interferometry with high-speed pixelated phase-mask camera

A Fizeau interferometer with instantaneous phase-shifting ability using a Wollaston prism is designed. To measure dynamic phase change of objects, a high-speed video camera of 10(-5)s of shutter speed is used with a pixelated phase-mask of 1024 x 1024 elements. The light source used is a laser of wavelength 532 nm which is split into orthogonal polarization states by passing through a Wollaston prism. By adjusting the tilt of the reference surface it is possible to make the reference and object beam with orthogonal polarizations states to coincide and interfere. Then the pixelated phase-mask camera calculate the phase changes and hence the optical path length difference. Vibration of speakers and turbulence of air flow were successfully measured in 7,000 frames/sec.