Intensity profile correction for data pages for holographic storage

Abstract

Intensity profile correction for data pages for holographic storage

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 shows a vertical cut through the material of a holographic recording medium having an inhomogeneous sensitivity distribution,

FIG. 2 shows the resulting contrast distributions within the recovered data pages,

FIG. 3 shows the bit error rate resulting from the inhomogeneous situation in FIG. 1b),

FIG. 4 schematically illustrates a method according to the invention, and

FIG. 5 depicts a holographic storage system according to the invention.

Claims

1. Method for recording data pages on a holographic recording medium, having the steps of: modulating a light beam with a spatial light modulator to generate a data page with data to be recorded, andapplying a compensation profile to the data pages during recording for reducing contrast variations in the reconstructed data pages,

2. Method according to claim 1, wherein the compensation profile is determined by successively writing and reading one or more test holograms and adjusting the compensation profile.

3. Method according to claim 1, wherein the compensation profile takes into account at least one of the profile of the light beam and contrast inhomogeneities caused by the optical setup.

4. Method according to claim 1, wherein the compensation profile is applied to the data pages by the spatial light modulator.

5. Method according to claim 1, wherein the compensation profile is applied to the data pages by an additional spatial light modulator.

6. Method according to claim 1, wherein the compensation profile is applied to the data pages by a filter.

7. Method according to claim 4, wherein the compensation profile is applied by modulating the intensity of the pixels of the data pages.

8. Holographic storage system, with a spatial light modulator for modulating a light beam in accordance with data to be recorded on a holographic recording medium, having a contrast variation compensator for applying a compensation profile to the data pages during recording for reducing contrast variations in the reconstructed data pages, wherein the compensation profile is determined by the irradiation history at the recording position and the sensitivity curve of the material of the holographic recording medium.

9. Holographic storage system according to claim 8, wherein the contrast variation compensator is the spatial light modulator, an additional spatial light modulator, or a filter.