[OPTICAL REVIEW Vol. 12, No. 2 (2005) 109-114]
© 2005 The Optical Society of Japan

Optical Differentiation Phase Measurement Using the Bias Shifting Method

Hideo FURUHASHI, Ryota SUGIYAMA, Yoshiyuki UCHIDA, Kiyofumi MATSUDA1 and Chander P. GROVER2

Department of Information Network Engineering, Aichi Institute of Technology, 1247 Yachigusa, Yakusa-cho, Toyota, Aichi 470-0392, Japan
1National Institute of Advanced Industrial Science and Technology, 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan
2Institute for National Measurement Standards, National Research Council Canada, M36, 1200 Montreal Road, Ottawa ON K1A OR6, Canada

(Received October 4, 2004; Accepted December 9, 2004)

A new optical phase measurement method using a differentiation filter is proposed. The new method uses two images obtained by shifting the filter. This method has an advantage in that non-uniformity of the wavefront intensity does not produce errors. We present herein the theory of the newly proposed method and verify the theory by computer simulation. The effects of non-uniformity of the wavefront intensity, noise, and bias shifting length for errors are discussed. The system has been demonstrated for a plane wave and a spherical wave. For the proposed method, although the number of errors due to noise increases, the number of errors due to non-uniformity decreases. Therefore, the proposed method is useful for the phase measurement of a wavefront for which the intensity is not uniform. In addition, it improves the accuracy of the phase measurement system using a differentiation filter.

Key words: phase measurement, optical differentiation, phase shifting, wavefront measurement