A closed-loop phase-shifting Fizeau-type interferometer at λ=633 nm was constructed with the direct frequency modulation of laser diodes. The interferometer is servo controlled fully in the phase domain where optical phases are detected by a two-frequency optical heterodyne method. Stepwise phase shifting was accomplished with good stabilization against external disturbances (vibration, air flow, etc.) and laser frequency fluctuations.
© 1998 Optical Society of America
(040.2840) Detectors : Heterodyne
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.2650) Instrumentation, measurement, and metrology : Fringe analysis
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(140.5960) Lasers and laser optics : Semiconductor lasers
Toshihiko Yoshino and Hiroshi Yamaguchi, "Closed-loop phase-shifting interferometry with a laser diode," Opt. Lett. 23, 1576-1578 (1998)