Study on large capacity optical data storage

为了实现只回放型全息存储，研究了使用不同深度凹坑图案的相位多值记录方法。由于在过去的ROM方法中多重性没有得到改善，因此检查了在凹坑深度方向上新记录多值的方法。阐明了利用电子束切割技术制作样品，可以在深度方向上制作八个台阶。对相位分集和零差检测进行了再现仿真。确认了相位，并确认能够通过8个值再现分离。今后还将进一步提高实验和模拟的准确性，并以提高存储容量为目标。

To achieve the holographics memory of the playback-only type, the phase multivalued record method to use the pit pattern with different depth was examined. Because the multiplicity had not improved in a past ROM method, the method to record multivalued newly in the direction of the pit depth was examined. It was clarified to be able to make eight steps for the direction of depth by using the electron beam cutting technology about the sample making. The phase diversity and the homodyne detection were simulated about the reproduction simulation. The phase was confirmed and it was confirmed to be able to reproduce the separation by eight values. The accuracy of the experiment and the simulation will be improved in addition in the future, and the improvement of storage capacity is aimed at.