SERVO CONTROL FOR HOLOGRAM INFORMATION STORAGE DEVICE, CAPABLE OF CONTROLLING THE POSITION OF REPRODUCED HOLOGRAM DATA BY CONTROLLING THE INCIDENT ANGLE OF REFERENCE BEAM FOR DISK

摘要

PURPOSE: A servo control for a hologram information storage device is provided to control an incident angle of a reference beam for a disk by controlling an angle of a flat glass, thereby controlling a position of reproduced hologram data. CONSTITUTION: When recording a hologram, a process is performed as follows. A signal beam(2) passes through an SLM(Spatial Light Modulator)(31) where a data image is displayed, and is Fourier-converted through 4-f relay lens systems(11). A reference beam(1) interferes with the signal beam(2) by using 4-f relay lens systems(21) to store data. When reproducing the hologram, a process is performed as follows. The signal beam(2) is cut off, and the reference beam(1) only is reflected to read stored information from a detector array(13).