Patent ID: 6301028
Filing Date: 2001-10-09
Classification: G03H,G11B

Abstract:
An optical information recording/reproducing apparatus for recording data on a holographic memory formed of a photorefractive crystal and reproducing data from the holographic memory, said apparatus comprising:a support portion for detachably supporting a holographic memory;a reference light beam supplying portion for supplying a coherent reference light beam of a first wavelength incident on the holographic memory;a signal light beam supplying portion for supplying a coherent signal light beam of the first wavelength, which is modulated in accordance with image data, incident on the holographic memory, to intersect the signal light beam with the reference light beam in the holographic memory thereby to generate a light interference pattern of the coherent signal light beam and the reference light beam; anda photo-detecting portion for detecting a diffracted light caused from a refractive index grating of the light interference pattern in the holographic memory caused by irradiation of the reference light beam;a mask portion disposed in a light path of the signal light beam so as to cover the light intensity distribution of the signal light beam incident into the holographic memory substantially at a half portion thereof with respect to the center of the zeroth-order diffracted light distribution of the signal light beam; anda moving portion for shifting the center of a region of the holographic memory in which the signal light beam and the reference light beam intersect with each other, by a distance substantially equal to twice the distance between peaks of the zeroth-order diffracted light or the first-order diffracted light of the signal light beam.