Hexagonal optical patterns in anisotropic non-linear media
Department of Optics and Fluid
Dynamics, Risø National Laboratory, Postbox 49, DK-4000 Roskilde, Denmark
We present experimental observations of hexagonal patterns in strongly anisotropic non-linear optical media. Close to threshold rolls are observed. As the non-linearity is increased a transition from rolls to hexagons, leading finally to a pure hexagonal state, is observed. A mean-field model, in agreement with experiments, shows that the anisotropy locks the far-field orientation of the hexagons, while leaving their rotational symmetry undisturbed.
PACS: 42.60.Jf – Beam characteristics: profile, intensity, and power; spatial pattern formation and dynamics / 42.65.Sf – Dynamics of nonlinear optical systems; optical instabilities, optical chaos, and optical spatio-temporal dynamics / 42.65.Hw – Phase conjugation, optical mixing, and photorefractive effect
© EDP Sciences, 1996