Holographic memory recording method and reproduction method, and holographic memory recording device and reproduction device

A hologram (A) generated by a signal beam and a partial reference beam (A), and a hologram (B) generated by an interference beam and a partial reference beam (B) are recorded in a specific location in a holographic memory. The specific location in the holographic memory is simultaneously irradiated with the partial reference beam (A) and the partial reference beam (B), simultaneously generating diffracted light of the hologram (A) and diffracted light of the hologram (B). From the diffracted light of the hologram (A) and the diffracted light of the hologram (B), the phase modulated signal contained in the signal beam is demodulated.