Transverse pattern formation for counterpropagating laser beams in rubidium vapor

Agnès Maître, A. Petrossian, A. Blouin +2 more

Vladimir A. Sautenkov, T. Varzhapetyan, Hebin Li +2 more

Vladimir A. Sautenkov, Mikhail N. Shneider, Sergey A. Saakyan +5 more

Alain Blouin, M. Pinard, Agnès Maître +3 more

Pattern formation in nonlinear systems is a very active subject in many areas of physics. For example, in hydrodynamics the arrangement of the convective cells of the Rayleigh-Bernard instability [1] constitutes a model problem for pattern formation. In optics, important advances have been recently obtained in the case of lasers [2]. In contrast, transverse pattern formation in mirrorless optical passive systems [3] is no so wellknown because of the intrinsic complexity of a system without cavity and of the fact that the first experiments were done with pulsed lasers [4], We present here results obtained with c.w. lasers and rubidium atoms. In particular, we show some interesting relationship with the hydrodynamics observations.

A. Petrossian, M. Pinard, Agnès Maître +2 more

An instability is observed when the intensity of two counterpropagating beams nearly resonant with the 5S1/2 → 5P1/2 transition of rubidium exceeds a threshold value. The instability manifests itself as a coherent emission on the polarization orthogonal to that of the incident beam with various spatial structures, depending on laser intensity and frequency. Bifurcation diagrams for the intensity of this instability with the associated transverse-pattern evolution are presented.

N. N. Badalyan, V. A. Iradyan, M. E. Movsesyan