Berlin 2001 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 11: Photoactive Materials
CPP 11.2: Talk
Thursday, April 5, 2001, 18:05–18:25, 110
Faster Response and Higher Sensitivity in Low-Tg Photorefractive Composites — •Erwin Mecher1, Francisco Gallego-Gomez1, Klaus Meerholz1, Felix Mielke2, and Oskar Nuyken2 — 1Physical Chemistry Department, University of Munich, Butenandtstr. 11, 81377 Munich — 2Macromolecular Chemistry, Technical University Munich, Lichtenbergstr. 4, 85747 Garching
Some of the most interesting applications for holographic storage media require reversible recording of holograms in real time. From the point of view of human perception real time means at least video-rate (30 frames/sec). To accomplish 30 write/erase cycles per second it is necessary to build up the external diffraction efficiency required by the application and erase it again within a time window of 33 ms or faster. In order to reach this goal under conditions typical for an application, i.e., moderate light intensities (ca. 100 mW/cm2), fast recording materials with high sensitivity are needed.
In this work we investigate photorefractive (PR) polymer composites as the reversible recording medium. We started from the well-known composites based on PVK doped with azo-dyes and replaced PVK by TPD-based hole-conducting polymers with higher hole mobility. We managed to decrease the response time by two orders of magnitude, while maintaining the excellent steady-state performance of the PVK-based composites. The suitability of the new PR material for video-rate holographic storage at moderate poling fields (ca. 80 V/micron) was proven in a simple plane-wave four-wave-mixing experiment.