Holographic storage medium

Abstract

The present invention relates to a holographic storage medium, and more specifically to a holographic storage medium which avoids the interference between a reference beam and a reconstructed object beam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding the invention shall now be explained in more detail in the following description with reference to the figures. It is understood that the invention is not limited to this exemplary embodiment and that specified features can also expediently be combined and/or modified without departing from the scope of the present invention. In the figures:

FIG. 1 schematically depicts a holographic pickup used in a holographic storage system,

FIG. 2 depicts a top view of a holographic storage medium according to the invention,

FIG. 3 illustrates the cross-section of the holographic storage medium according to the invention,

FIG. 4 schematically shows the propagation of the object beam through the holographic storage medium during recording,

FIG. 5 depicts the propagation of the reference beam and the reconstructed object beam during read-out,

FIG. 6 illustrates a holographic storage medium according to the invention using a structured area, and

FIG. 7 shows a top view of a rectangular holographic storage medium according to the invention.

Claims

1. Holographic storage medium with a holographic storage layer on top of a reflective layer, the reflective layer having non-reflective areas as well as reflective areas for coupling a reference beam out of the optical path of a reconstructed object beam, wherein the non-reflective areas are arranged besides an area of the holographic storage layer where holograms are recorded.

2. Holographic storage medium according to claim 1, further having a spacer layer between the holographic storage layer and the reflective layer.

3. Holographic storage medium according to claim 1, wherein the holographic storage medium is a disk-shaped storage medium.

4. Holographic storage medium according to claim 3, wherein the non-reflective areas are concentric rings or a spiral, or a plurality of individual non-reflective areas arranged in concentric rings or a spiral.

5. Holographic storage medium according to claim 1, wherein the holographic storage medium is a card-shaped storage medium.

6. Holographic storage medium according to claim 5, wherein the non-reflective areas are lines or a plurality of individual non-reflective arranged in lines.

7. Holographic storage medium according to claim 1, wherein the non-reflective areas are transparent or absorbing areas.

8. Apparatus for reading and/or recording a holographic storage medium with a holographic storage layer and a reflective layer, having a light source for generating a reference beam used for generating a reconstructed object beam, wherein the reference beam is arranged inclined with respect to the optical path of the reconstructed object beam such that either the reference beam impinges on non-reflective areas of the reflective layer or the reconstructed object beam impinges on non-reflective areas of the reflective layer.

9. Apparatus according to claim 8, wherein the focus of the reference beam is situated in the reflective layer