Patent ID: 8305668

Claim:
A recording and reproducing device for performing recording and reproduction onto and from a hologram recording medium on which data is recorded by using interference fringes between a reference beam and a signal beam, the device comprising: a phase modulation unit configured to include at least a phase modulator performing spatial light phase modulation for incident light on a picture element-by-picture element basis and having a signal beam area serving as an area for generating the signal beam and a reference beam area serving as an area for generating the reference beam set therein and configured to provide a phase difference between a beam passing through the reference beam area and a beam passing through the signal beam area; an optical section configured to guide light emitted from a light source and obtained through the phase modulation unit to the hologram recording medium; a light-shielding unit configured to be inserted in a specific position in the optical section and to at least shield a beam passing through a gap area between the signal beam area and the reference beam area in the phase modulator; and a phase control unit configured to perform phase control for the phase modulator; wherein at a time of recording, said phase control unit controls individual picture elements of the phase modulator in such a manner that a phase modulation pattern within the signal beam area is set to a pattern corresponding to recording data and a phase modulation pattern within the reference beam area is set to a specific pattern and for performing, and at a time of reproduction, said phase control unit controls the individual picture elements in such a manner that a phase difference of π/2 is provided as a phase difference between an entire phase of a direct current (DC) beam emitted from the phase modulation unit through the signal beam area and a reference phase within a reference beam emitted from the phase modulation unit through the reference beam area.