[OPTICAL REVIEW Vol. 17, No. 3 (2010) 195-203]
© 2010 The Japan Society of Applied Physics

All Optical Phase-Only Filtering Correlation with Binarized Inputs by a Ferroelectric Liquid-Crystal Spatial Light Modulator

Takeshi TAKAHASHI* and Yukihiro ISHII1

Department of Telecommumination System Engineering, University of Industrial Technology, Sagamihara, 4-1-1 Hashimotodai, Sagamihara, Kanagawa 252-5196, Japan
1Department of Applied Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan

(Received October 9, 2009; Accepted February 11, 2010)

All optical phase-only filtering correlator is constructed with an optically addressed ferroelectric liquid-crystal spatial light modulator (FSLM) for a binarized input object and a twisted-nematic liquid-crystal spatial-light modulator for a computer-generated phase-only filter. In order to improve the discrimination capability of a phase-only filtering correlator, a binarized amplitude with maximum contrast in a FSLM is used for an object input. The contrast of binarized intensities can be maximized by adjusting the rotation angles of a FSLM and polarizers. The threshold level of binarized input objects can be controlled by changing the power of a laser incident on a FLSM. Experimental results with a high discrimination capability are presented to support the numerical correlation performance.

Key words: ferroelectric spatial light modulator, binarization procedure, correlation performance, phase-only filter, real-time optical processing

*E-mail address: take@uitec.ac.jp