Thomson Licensing

Hahn-Schickard-Gesellschaft Fur Angewandte Forschung E.v.

Heiko Trautner

Hartmut Richter

Joachim Knittel

Christof Ballweg

Dietmar Braeuer

The present invention relates to a holographic recording medium adapted to store additional information for the recorded holograms, and to a holographic pickup for a holographic storage system for use with the holographic recording medium. According to the invention, the holographic recording medium has a holographic layer for storing holograms and a servo layer for positioning a light beam for reading and/or recording of a hologram relative to the holographic recording medium, wherein the servo layer is recordable or rewritable. A holographic pickup for use with such a holographic recording medium includes a light source for recording additional data in the servo layer of the holographic recording medium.

Holographic recording medium having a track pitch smaller than a distance between adjacent holograms

An apparatus for reading from a multilayer holographic storage medium with a coaxial arrangement of a reference beam and a reconstructed object beam is described. The apparatus has an objective lens for focusing the reference beam into the multilayer holographic storage medium such that the reference beam has a focal point behind or in front of a reflective layer of the multilayer holographic storage medium, wherein a distance between the objective lens and the multilayer holographic storage medium is set in accordance with an addressed layer of the multilayer holographic storage medium, and an imaging system with a fixed lens of focal length f and a movable lens of focal length f for re-collimating a reconstructed object beam, wherein for a specific position of the movable lens the imaging system assumes aconfiguration. For re-collimating the reconstructed object beam the apparatus is adapted to shift the movable lens of theimaging system by substantially twice the shift of the objective lens necessary for addressing a specific layer of the multilayer holographic storage medium.

Multilayer coaxial holographic storage system

A holographic recording medium with an improved servo structure is presented. The holographic recording medium has a hologram layer for storing holograms and a servo layer for positioning a light beam for reading and/or recording of a hologram relative to the holographic recording medium. The servo layer is an essentially flat dye recording layer. A holographic pickup for use with such a holographic recording medium includes a light source for generating a light beam, which interacts with the dye recording layer for recording servo information.

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Unterkirnach, Germany

Heiko Trautner