par Santagiustina, Marco;Colet, Pere;Miguel, Maxi San;Walgraef, Daniel 
Référence Journal of optics. B, Quantum and semiclassical optics, 1, 6, page (191-197)
Publication Publié, 1999-12
Référence Journal of optics. B, Quantum and semiclassical optics, 1, 6, page (191-197)
Publication Publié, 1999-12
Article révisé par les pairs
| Résumé : | Pattern formation in nonlinear optical cavities, when an advection-like term is present, is analysed. This term breaks the space inversion symmetry causing the existence of a regime of convective instabilities, where noise-sustained structures can be found, and changing the pattern orientation and the selected wavevector. The concepts of convective and absolute instability, noise-sustained structures and the selection mechanisms in two dimensions are discussed in the case of optical parametric oscillators and a Kerr resonator. In the latter case, in which hexagons are the selected structure, we predict and observe that stripes are the most unstable structures in the initial linear transient. In the nonlinear regime of the absolute instability these stripes destabilize and hexagons form. Their orientation is dictated by that of the transient stripes and therefore by the advection term. In the convective regime we predict and observe disordered noise-sustained hexagons, preceded in space by noise-sustained stripes. © 1999 IOP Publishing Ltd. |
