High-speed Fizeau interferometry and digital holography for dynamic phenomena measurement

An optical system based on a Fizeau interferometer with instantaneous phase-shifting using a Wollaston prism is presented. To measure dynamic phase change of objects, a high-speed video camera of 10−5 s with a pixelated phase-mask. The laser light is split into orthogonal polarization states by passing through a Wollaston prism. Then the beam is passed through expanding and collimating optics onto a sample through a half mirror. The half mirror acts as the reference surface. The light beams reflected back from the sample and the reference half mirror are filtered with a pin hole and arrives at the pixelated camera. 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. Digital holography based on this system is also discussed.