Sony Unveils Results on Four-layer Micro-Reflector Holographic Recording
Category: Storage Date: May 23rd, 2007
Sony Corp. presented its achievements on data reading/writing on a medium equivalent to four-layer disc with the use of Micro-Reflector recording, a type of holographic recording. Thus far, the company has unveiled the results only on a single-layer medium.
In the Micro-Reflector recording, light beams are irradiated on both sides of the recording medium. Two light beams are then interfered on the recording layer by aligning their focal points, thereby recording an interference fringe which corresponds to 1-bit information capacity. The information is reproduced by emitting light on the front side of the medium. Interference fringes with different depths can be recorded by changing the depth of the focal points as in the case of recording on a multilayered medium.
In addition to multilayer recording, the company points out advantages in that the method is less likely to be influenced by the expansion/contraction of photopolymer due to heat, thus preventing signal reading errors. This is because the interference fringes are smaller than those used in other holographic recording methods where recording is performed on a page basis. The company expects that the Micro-Reflector system will easily facilitate reductions in equipment cost because it can utilize existing blue-violet semiconductor laser diodes and eliminate the need of a spatial phase modulator, CMOS sensor or other parts.