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5 February 1990 Computer-Generated Hologram Design For A Magneto-Optic Spatial Light Modulator
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A magneto-optic spatial light modulator (MOSLM) has been proposed for use as a Fourier plane filter in a coherent optical correlator. Its binary nature and limited, presently small, space-bandwidth product constrain any filter design. Although binary quantization allows a maximum number of Fourier values to be coded, quantization and reconstruction error is high except in a few cases. To reduce these errors, a cell-oriented binary coding technique, the delayed-sample method, is used. Three cell sizes are considered: 2 x 1 pixels, 3 x 1 pixels, and 4 x 1 pixels. Through coding, a 2 x 1 cell can realize three real values {-1,0,1} as opposed to only two {4,1} for binary quantization; however, there is a trade-off in the number of Fourier values that can be coded. For a 2 x 1 cell the number is reduced by one-half. A 3 x 1 cell can realize seven complex values, but with a one-third reduction in the number of coded Fourier values. Finally, a 4 x 1 cell is capable of realizing nine complex values with a one-fourth reduction in the number of coded values. The trade-off between quantization error and number of Fourier values coded is examined qualitatively using a 128 x 128 MOSLM. Reconstructions from coding using different cell sizes are compared to reconstructions from binary quantization. In addition to coding, hologram replication is used to improve reconstruction error. Sampling issues relating to the size of the filter response are also discussed.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Glenn S. Himes and Joseph N. Mait "Computer-Generated Hologram Design For A Magneto-Optic Spatial Light Modulator", Proc. SPIE 1151, Optical Information Processing Systems and Architectures, (5 February 1990);

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