Berlin 2005 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 5: Poster Nichtlineare Optik

Q 5.10: Poster

Freitag, 4. März 2005, 11:00–12:30, Poster HU

Control by pump beam detuning of a photorefractive single-mirror feedback system
— •Christian Ripperda, Philip Jander, and Cornelia Denz — Institut für Angewandte Physik, Westfälische Wilhelms-Universität, Corrensstrasse 2, 48149 Münster

Single feedback systems employing a photorefractive bulk medium as nonlinearity are known to exhibit a variety of transverse patterns [1]. In addition to predominant hexagonal patterns, stripes, squares and squeezed hexagons can be observed to coexist and compete, providing bistable parameter regions. In a parameter range where a bistability between two different patterns exists, detuning of the counterpropagating pump beams is known to change the linear stability [2].

We experimentally demonstrate deterministic switching between square and squeezed hexagonal patterns by pump beam detuning and investigate its suitability as a control method depending on the distance in parameter space from the bistability. Additionally, we present an analysis of the effect of pump detuning on fundamental unstable modes. Experimental results are compared to predictions obtained by means of a linear stability analysis.

[1] M. Schwab, C. Denz, M. Saffman, Appl. Phys. B 69, 429-433 (1999)

[2] M. Schwab, C. Denz, A.V. Mamaev, M. Saffman, J. Opt. B 3 318-327 (2001)