Optical computing by a vector holographic memory system

We propose what is to our knowledge a novel holographic memory system that is simultaneously applicable to data storage and optical computing. We introduce a polarization-modulated reference beam into holographic recording. A desired spatial-frequency component of an object beam is recorded as a polarization-modulated grating, and the other component is recorded as an intensity-modulated grating. Since the polarization-modulated grating rotates the polarization axis of the incident light by 90 degrees , it is possible to distinguish the desired spatial-frequency component of the retrieved image. Utilizing this property, we have successfully performed spatial-frequency filtering and frequency-selective matched filtering. The system is capable of a variety of optical computations, depending on the design of the polarization modulation.