Takeshi TAKAHASHI^1*, Yukihiro ISHII^2,3†, and Ribun ONODERA¹

¹Department of Electronic and Information Systems Engineering, Polytechnic University, Kodaira, Tokyo 187-0035, Japan
²Department of Applied Physics, Tokyo University of Science, Katsushika, Tokyo 125-8585, Japan
³Photonics Control Technology Team, RIKEN, Wako, Saitama 351-0198, Japan

(Received October 28, 2013; Revised December 6, 2013; Accepted December 10, 2013)

A phase-shifting interferometer with a tunable external-cavity laser diode has been constructed for forming three-dimensional (3-D) phase profiles. The interference phase is shifted equally in four steps by varying the source wavelength. Profilometry is achieved by measuring the phase shifts that are extracted by the Carré algorithm. The linear regression of the distance measurement from 40 μm to 13 mm has been experimentally demonstrated by phase-shifting interferometry. A laser-diode interferometer has been applied to 3-D profile measurement for a step-mirror object at a deep depth.

Key words: phase-shifting interferometry, tunable laser diode, profilometry, Carré algorithm

^*E-mail address: take@uitec.ac.jp
^†E-mail address: y.ishii@rs.kagu.tus.ac.jp