On-off laser diode control for phase retrieval in phase-shifting interferometry

This paper describes an alternative automated setup for phase-shifting and phase retrieval based on the wavelength tunability of a laser diode. For many industrial and scientific applications it is desirable that the laser gets stabilized. In this paper, on the contrary, the laser diode is turned on and off for a short period of time. The generated variations of voltage and temperature cause a modulation of its wavelength. This modulation is used for a simple demonstration of the phase-shifting phenomena and phase retrieval under the scheme of an unbalanced Twyman-Green interferometer and using the Carre algorithm. The on-off switching of the laser can be done manually, but for this proposal, it will be emulated by a pulse voltage signal from a data acquisition device. (C) 2015 Optical Society of America