Striped and circular domain walls in the DOPO

A family of circular and striped domain walls with oscillatory tails have been observed with the propagation model for the DOPO that is more general than the mean-field model. The same structures are observed with diffraction inside or outside the cell, showing that diffraction and nonlinearity may be decoupled. They result from the switching of the signal amplitude, from the positive to the negative solution. They are formed for positive and negative signal detunings of order unity, in a wide range of input pump amplitude. A second-order MacLaurin expansion mapping model is found to agree well with the propagation model.