Berlin 2001 – wissenschaftliches Programm

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Q: Quantenoptik

Q 13: Nonlinear Optics I

Q 13.6: Vortrag

Dienstag, 3. April 2001, 17:00–17:15, H 2013

Ultrafast transient index grating: efficient frequency conversion, instantaneous optical switching and simple logic operations on a femtosecond time scale — •Reiner P. Schmid¹, Thomas Schneider², and Jürgen Reif¹ — ¹Brandenburgische Technische Universität Cottbus, Universitätsplatz 3-4, 03044 Cottbus, Germany — ²Deutsche Telekom AG, Fachhochschule Leipzig, Gustav-Freytag-Str. 43-45, 04277 Leipzig, Germany

The phenomenon of transient optical gratings generated from interfering laser beams has been studied intensively for a long time. A general feature in most of these investigations was the fact that these gratings represented a quasi steady state and were present, usually, in the whole sample. With the advent of state-of-the-art ultrashort pulse lasers, a new feature has entered the game: due to the high intensity achievable, non-resonant processes can be exploited for the formation of the grating which, hence, appears and disappears instantaneously with the laser pulses. Because of the short spatial extension of the pulses, the grating is of comparable thickness and travels through the sample together with the light. In this contribution, we report on new phenomena, associated with this new feature: we observe strong third harmonic generation with an efficiency of several percent due to self-phase matching, and we show how diffraction and self diffraction by the grating can be exploited for ultrafast optical switching and simple logic operations.