摘要 |
In one embodiment, a holographic data storage medium (60) includes a substrate (61, 62), a holographic recording material (63), and an optically detectable tracking pattern (64) on the medium (60). The substrate may have first (61) and second (62) substrate portions. The holographic recording material (63) may be a photopolymer, and the medium (60) may have a sandwiched construction, where the holographic recording material (63) is sandwiched between the first (61) and second (62) substrate portions. The optically detectable tracking pattern (64) may be replicated on at least one of the substrate portions. Alternatively, the optically detectable tracking pattern (64) may be recorded as a holographic grating in the holographic recording material (63). The tracking pattern (64) may facilitate the ability to pinpoint the location of the holographic bit maps on the holographic medium (60) to within a fraction of a micron. |