Three-dimensional multiplexing method with spherical reference beam

Today, along with the wider use of high-speed information networks and multimedia, it is increasingly necessary to have higher-density and higher-transfer-rate storage devices. Therefore, research and development into holographic memories with three-dimensional storage areas is being carried out to realize next-generation large-capacity memories. The mainstream in the world is the angle multiplexing method, however, it costs too much and its control is quite severe. In such situation, we study about shift multiplexing method because it costs not much and its control is easier than the angle multiplexing. In this experiment, we examined shift selectivity of track direction, radial direction and vertical direction of the medium. As a result, combining these different kinds of selectivity, we found a possible multiplexing way to achieve several tera bits per inch square density recording.