how holographic data storage works

For holographic information recording, first a laser ray is divided in two. Then one of the resulting rays is passed through a Spatial Light Modulator (SLM) that converts configurations of electronic data into white and black configurations in the laser beam. This ray becomes the "signal" ray. The second ray becomes the "reference" ray. Then the two rays are focused and intersected within an optically sensitive storage media. This intersection makes a chemical reaction between the storage medium and the configuration of overlapping peaks and troughs of the two beams of light. This burns the data into the storage media in the form of a hologram. To retrieve the data, a ray with the same wavelength and angle as the source reference beam is focused within the recordable media, the signal beam is retrieved, and the light and dark patterns are converted back into electronic information through the use of a Digital Camera Detector (DCD). Three-dimensional holographic information storage can store considerably more data in the same size object than can surface-only, information storage systems such as present day CDs and DVDs. The page on Lenticular Printing Software For 3D Holograms discusses some of these issues as well.

Holographic information storage imprints data, one million bit holographic image at once, throughout the thickness of a photosensitive media like polycarbonate material. When these holograms are lit by a laser beam with the same wave phase and angle used to form them, then the information is recreated and may be read via computer. For Holographic Read Only Memory (HoloROM), the photodiode part of a traditional ROM player is changed to a CMOS camera chip. Reconstructed information is projected onto the camera. Photorefractive crystals have potential for rewritable storage. Also, Virtual Reality may be of interest.

Also, Holographic Data Cards includes coverage of this material.