Optical rogue waves in an all solid state laser with saturable absorber: importance of the spatial effects

Abstract

We study the features of the optical rogue waves (ORWs) observed in an all-solid-state (Cr:YAG C Nd:YVO4) passively-Q-switched laser, which is a system of wide practical interest. The extreme events appear as isolated pulses of extraordinary intensity during the chaotic regime of this laser. The standard theoretical description (three-level rate equations for a single mode of the field and a two-level system for the absorber) does predict the existence of many of the observed dynamical features, including chaos, but it fails to predict the existence of ORWs. Faced with the problem of improving the theoretical description, we find that ORWs are observed only when the Fresnel number of the laser cavity and the embedding dimension of the attractor reconstructed from the experimental time series are high, and the laser spot profile has a spatially complex structure. These results suggest that spatial effects are an essential ingredient in the formation of ORWs in this type of laser.