| Institution: | Laboratoire de Physique des Lasers, Atomes, Molécules, UMR CNRS 8523, Centre de Recherches Lasers et Applications, UFR de Physique, Bât. P5, Université des Sciences et Technologies de Lille, F-59655 Villeneuve d'Ascq, France |
| Abstract: | We report on the observation of fast oscillations at frequencies of a few MHz in a triply resonant optical parametric oscillator. These oscillations can appear alone, or superimposed on slow oscillations due to thermo-optical instabilities, and display a great variety of waveforms. The analysis of the regimes observed experimentally leads us to conjecture that the mechanism responsible for this instability is not the Hopf bifurcation of the single-mode mean-field model, but that it is based on the interaction of two signal fields oscillating in cavity modes with neighboring frequencies. This interpretation is supported by numerical simulations of the mean-field model with two coupled modes, which reproduce well the behaviors observed experimentally. We also find chaotic solutions of this model, which unveils another possible scenario leading to deterministic chaos in this system. |
