Excitability mediated by localized structures in a dissipative nonlinear optical cavity

4 pages.-- PACS nrs.: 42.65.Sf, 05.45.–a, 89.75.Fb.-- ArXiv pre-print: http://arxiv.org/abs/nlin.PS/0411047We find and characterize an excitability regime mediated by localized structures in a dissipative nonlinear optical cavity. The scenario is that stable localized structures exhibit a Hopf bifurcation to self-pulsating behavior, that is followed by the destruction of the oscillation in a saddle-loop bifurcation. Beyond this point there is a regime of excitable localized structures under the application of suitable perturbations. Excitability emerges from the spatial dependence since the system does not exhibit any excitable behavior locally. We show that the whole scenario is organized by a Takens-Bogdanov codimension-2 bifurcation point. DOI: 10.1103/PhysRevLett.94.063905We acknowledge financial support from MEC (Spain) and FEDER: Grant Nos. BFM2001-0341-C02-02, FIS2004-00953, and FIS2004-05073-C04-03. D.G. acknowledges financial support from EPSRC (GR/S28600/01).Peer reviewe