Collinear Phase Lock Holographic Memory

Collinear phase-lock holography using phase-modulated data pages was proposed for holographic multi-level recording. Record
Fig.1 shows optical system for collinear phase-lock holography. The recording process of collinear phase-lock holography is similar to that of collinear holography except for recording data pages. In collinear phase-lock holography, phase-modulated data pages which are generated by spatial light phase modulator are used.
Fig. 1 Record principle of the collinear phase-lock holography.

Read out
 Fig.2 shows the schematic drawing of read out by the collinear phase-lock holography. In the retrieving process of collinear phase-lock holography, reference beam and phase-lock beam are illuminated. Phase-lock beam has uniform amplitude and phase and passes common path of signal beam. Then phase interference of signal beam and phase-lock beam is carried out in order to convert phase-modulated data pages to amplitude-modulated data pages.
Fig. 2 Read out principle of the collinear phase-lock holography.