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Regular Paper[OPTICAL REVIEW Vol. 7, No. 2 (2000) 158-163] Phase-Shifting Fringe Analysis for Laser Diode Wavelength-Scanning InterferometerJun-ichi KATO and Ichirou YAMAGUCHI Optical Engineering Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1, Hirosawa, Wako, Saitama, 351-0198 Japan (Received November 8, 1999; Accepted December 14, 1999) A method for analyzing the fringe patterns obtained from a wavelength-scanning interferometer is proposed. It is based on phase retrieval with the phase-shifting method and derivation of its slope along the wave number axis. The accuracy and the error sources are estimated by experiments, in which a laser diode under small wavelength-modulation (~95 pm) is used as the light source. A conventional piezoelectric phase shifter was used for a phase shifter. This technique can be applied to profile measurement of stepped objects located across the zero-path position. Key words: wavelength scanning interferometry, profile measurement, laser diode, phase-shifting technique, stepped object |
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