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Q: Quantenoptik

Q 212: Nichtlineare Optik I

Q 212.3: Talk

Tuesday, March 5, 2002, 14:30–14:45, HS 22/108

Transverse scale of patterns in a feedback system with photorefractive nonlinearity — •Philip Jander, Oliver Kamps, and Cornelia Denz — Institut für Angewandte Physik, Westfälische Wilhelms-Universität Münster, Corrensstr. 2/4, 48149 Münster, Germany

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. The unstable transverse wave number leading to the formation of patterns is predicted by a linear stability analysis [2].

We present detailed analysis of the transverse scale of the spatial patterns depending on the control parameter of photorefractive coupling and the feedback phase of the reflected beam. The results are compared with predictions obtained by means of the linear stability analysis. For the parameter range in which multiple patterns are stable, a significant discrepancy is reported, illustrating the need for a more detailed analysis.

In addition, a comparison of pattern scales observed under one- and two-dimensional boundary conditions is presented. The relevance of interaction between unstable modes for the formation of non-hexagonal patterns is discussed.

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

[2] T. Honda, P. Banerjee, Opt. Lett. 21, 779–781 (1996)