Hologram Memory with High Quality and High Information Storage Density –Hologram Memory–

A hologram memory with the information storage density of 10 5 bits/mm 2 is realized by the RPS (Random Phase Shifter) method. The storage density is in the region of the theoretical limit predicted from the characteristics of the optical system. It is visualized by experiments and numerical calculations that by the RPS method the hologram memory of higher quality and higher information storage density can be made than by the commonly used defocussing method. For the future target, hologram memory of storage density of 10 7 bits/mm 2 is suggested through the considerations of the theoretical limit from the storage medium.