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Q: Quantenoptik

Q 16: Optische Technik

Q 16.8: Vortrag

Dienstag, 4. April 2000, 18:15–18:30, HS VI

Microgratings for optical data storage — •Steffen Ulm — Technische Universitaet Berlin, Optisches Institut, Sekr. P1-1, Strasse des 17. Juni 135, 10623 Berlin

The limitations of the storage capacity of conventional optical disks may be overcome by recording the digital data holographically as microscopic reflection gratings. For writing, a laser beam is focused within the storage layer and then reflected from the reflecting unit on the other side of the disk. To retrieve the stored data, the information is reconstructed by reflection of the read beam at the induced grating. As the modulation range of microholograms is strongly confined in all directions, they can be packed very dense in a single plane of the storage medium. Multilayer storage becomes also possible. Due to the Bragg-selectivity of holographic volume gratings, several microholograms can be stored in the same volume by using write beams of different wavelengths. High storage density may be achieved by combining the wavelength mutliplexing and multilayer storage. All bits contained in one multiplexed microhologram can be recorded in parallel by using different wavelengths simultaneously. Dynamic recording and readout of wavelength-multiplexed microholograms in DuPont photopolymers is reported.