Optical information recording and reproducing apparatus using a volume holographic memory

摘要

A description is provided of an optical information recording and reproducing apparatus which detachably supports a volume holographic memory formed of a photorefractive crystal. The apparatus includes a portion for supplying a coherent reference light beam at a first wavelength into the volume holographic memory; a portion for supplying a coherent signal light beam at the first wavelength, modulated in accordance with image data, into the memory to produce an optical interference pattern with the reference light within the memory; a portion for supplying a gate light beam at a second wavelength into the memory for activating or deactivating an index grating in accordance with the presence or absence of the optical interference pattern to enhances a photo-sensitivity of the memory; and a detector for detecting diffraction light from the index grating of the memory by the irradiation of the reference light beam. The apparatus includes a scanning portion for moving an intersecting region in which the gate light beam, the signal light beam and the reference light beam intersect with one another within the volume holographic memory along an optical axis of an optical path of the signal light beam within the volume holographic memory.