Patent ID: 8072660

Claim:
A hologram recording apparatus for recording a hologram in a recording layer of a holographic recording medium by causing a signal light beam modulated in accordance with data to be recorded to interfere with a reference light beam, the signal light beam and the reference light beam being emitted from the same light source, the hologram recording apparatus comprising: a signal-beam spatial light modulating section on which a signal light beam pattern for generating the signal light beam is displayed; a reference-beam spatial light modulating section on which a reference light beam pattern for generating the reference light beam is displayed; and a control unit for controlling the shape of the signal light beam pattern displayed on the signal-beam spatial light modulating section and the shape of the reference light beam pattern displayed on the reference-beam spatial light modulating section; wherein a data-recording signal light beam pattern serving as a signal light beam pattern in accordance with the data to be recorded is displayed on the signal-beam spatial light modulating section, and a data-recording reference light beam pattern identified so as to correspond to the data-recording signal light beam pattern is displayed on the reference-beam spatial light modulating section so that a data-recording hologram is formed in a predetermined area of the recording layer and wherein an encryption signal light beam pattern serving as a signal light beam pattern for encrypting the data-recording hologram is displayed on the signal-beam spatial light modulating section, and an encryption reference light beam pattern having a shape different from the data-recording reference light beam pattern is displayed on the reference-beam spatial light modulating section so that an encryption hologram is formed in the same area as the predetermined area of the recording layer, wherein the data-recording hologram and the encryption hologram are overwritten in said predetermined area to form an encrypted hologram.