Experimental characterization of domain walls dynamics in a   photorefractive oscillator
  We report the experimental characterization of domain walls dynamics in a photorefractive resonator in a degenerate four wave mixing configuration. We show how the non flat profile of the emitted field affects the velocity of domain walls as well as the variations of intensity and phase gradient during their motion. We find a clear correlation between these two last quantities that allows the experimental determination of the chirality that governs the domain walls dynamics. 
Adolfo Esteban, Victor B. Taranenko, Javier Garcia, Eugenio Roldan and   German J. de Valcarcel