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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.132: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Discrete soliton mobility in two-dimensional waveguide arrays with — •Rodrigo Vicencio¹ and Magnus Johansson^1,2,3 — ¹Max-Planck-Institut für Physik Komplexer Systeme — ²Department of Physics, Chemistry and Biology (IFM), Linköping — ³University of Kalmar, Department of Chemistry and Biomedical

We address the issue of mobility of localized modes in two-dimensional nonlinear Schrödinger lattices with saturable nonlinearity. This describes e.g. discrete spatial solitons in a tight-binding approximation of two-dimensional optical waveguide arrays made from photorefractive crystals. We discuss numerically obtained exact stationary solutions and their stability, focussing on three different solution families with peaks at one, two, and four neighboring sites, respectively. When varying the power, there is a repeated exchange of stability between these three solutions, with symmetry-broken families of connecting intermediate stationary solutions appearing at the bifurcation points. When the nonlinearity parameter is not too large, we observe good mobility, and a well defined Peierls-Nabarro barrier measuring the minimum energy necessary for rendering a stable stationary solution mobile.