A simple interferometer for measuring both relative displacement and absolute distance is fabricated that uses a laser diode. The sign of the displacement is detected by means of a λ/8 plate, and the distance is measured by a FM radar technique of modulating the laser-diode frequency. Measurement accuracies of 0.02 μm for displacement and 100 μm for distance are obtained over a range of a few meters.
© 1987 Optical Society of America
Original Manuscript: December 30, 1986
Manuscript Accepted: February 5, 1987
Published: May 1, 1987
Toshihiro Kubota, Makoto Nara, and Toshihiko Yoshino, "Interferometer for measuring displacement and distance," Opt. Lett. 12, 310-312 (1987)