Nonlinear Effects in Photonic Materials - Abstract
Taki, Majid
Spatial dissipative solitons (or localized structures) in extended systems has attracted much attention in fields as different as physics, hydrodynamics, chemistry, and biology. Nonlinear optics, in particular, represents a fruitful area of activity. This is due to the fact that, on the one hand, dissipative solitons arise naturally in many optical systems from the interplay of diffraction, nonlinearities and dissipation. On the other hand, nonlinear optical devices have recently appeared as very promising devices for their potential applications, including low-noise measurement and detection, information technology, and image processing. In this contribution we first give a brief introduction of the origin of transverse effects giving rise to spatio-temporal instabilities in spatially extended nonlinear optical systems. This enables us to emphasize the importance of pattern forming instabilities in the occurrence and dynamics of dissipative solitons. Second, we focus our investigations on the impact of non linear effects in the formation and the dynamics of dissipative solitons in optical parametric oscillators. Here, non local effects mainly result from advection (drift stemming from the crystal anisotropy or walk off) and inhomogeneous pumping that are largely encountered in the experiments. We show that they drastically affect the formation, the shape, and the dynamics of the solitons. In particular, we have identified and analytically characterized new convective and absolute instabilities giving rise to trapped solitons in monostable regime. In bistable regime, our analytical investigations show the crucial role of non local effects in the nonlinear dependence of the frequency and velocity of dissipative solitons on their intensity. This makes it possible to explain the self-frequency shift, the slowing down and the nonlinear symmetry breaking observed in the envelope of dissipative solitons emitted by optical parametric oscillators.