Method Combining Focus-Shift and Angle Multiplexing Method for Holographic Data Storage

Holographic data storage capacity is proportional to the thickness of a photopolymer recording medium. To maximize the performance of a photopolymer recording medium, it is necessary to develop a multiplexing technique that has sensitivity in the vertical direction of the medium. As a method to achieve this, we suggest the focus-shift multiplexing method by which holograms are recorded in the vertical direction of the medium. By combining angle multiplexing and this focus-shift multiplexing, we confirm that the multiplexed holograms that are recorded by angle multiplexing are well spatially separated in the vertical direction of the medium, and these holograms can be reconstructed without crosstalk noise.