An Asynchronous Image Subtracting Optically Addressed Spatial Light Modulator

The operation of image-subtraction is useful in optical processing. We report the first asynchronous image-subtracting optically addressed spatial light modulator incorporating a ferroelectric liquid crystal and a color-sensitive a-Si:H p-i-n-i-p photodetector. We present experimental results characterizing the sensitivity of the photodetector current-voltage characteristics to wavelength, and demonstrate image subtraction. Finally, we propose a model that explains the operation of the image-subtracting OASLM.