Instabilities of waves in nonlinear disordered media
We develop a self-consistent theory of temporal fluctuations of a speckle pattern resulting from the multiple scattering of a coherent wave in a weakly nonlinear disordered medium. The speckle pattern is shown to become unstable if the nonlinearity exceeds a threshold value. The instability is due to a feedback provided by the multiple scattering and manifests itself in spontaneous fluctuations of the scattered intensity. The development of instability is independent of the sign of nonlinearity.
Skipetrov
SE
Laboratoire de Physique et Modelisation des Milieux Condenses, Universite Joseph Fourier, Maison des Magisteres-CNRS, BP 166, 38042 Grenoble Cedex 9, France.
Maynard
R