Experimental characterization of quasiperiodic route to chaos in a VECSEL with SESAM.

We analyze the temporal dynamics of an optically-pumped quantum well vertical external-cavity surface-emitting laser (VECSEL) with a Semiconductor Saturable Absorber Mirror (SESAM) using the time series obtained when varying the pump power. We unveil the quasiperiodic route to chaos in the system by characterizing the Fourier spectra, the attractors in phase space, and the Lyapunov exponents for each temporal behavior observed: periodicity, quasiperiodicity, and chaos. Thus, we provide a complete description of this experimental observation of the route to chaos in a VECSEL-SESAM system.

Polarization dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror.

We investigate experimentally the polarization dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror in the cavity. We demonstrate that the normalized Stokes parameters and degree of polarization are functions of time reaching extreme values around the pulse peaks. Our experiments show that light is elliptically polarized, being able to have a circular right-handed or left-handed component, depending on the orientation of the saturable absorber mirror.

Extended stable equilibrium invaded by an unstable state.

Coexistence of states is an indispensable feature in the observation of domain walls, interfaces, shock waves or fronts in macroscopic systems. The propagation of these nonlinear waves depends on the relative stability of the connected equilibria. In particular, one expects a stable equilibrium to invade an unstable one, such as occur in combustion, in the spread of permanent contagious diseases, or in the freezing of supercooled water.

Front propagation transition induced by diffraction in a liquid crystal light valve.

Driven optical systems can exhibit coexistence of equilibrium states. Traveling waves or fronts between different states present complex spatiotemporal dynamics. We investigate the mechanisms that govern the front spread.