DARK SOLITONS GENERATED BY 2ND-ORDER PARAMETRIC INTERACTIONS

We show that parametric interactions in quadratic nonlinear media can support a novel type of spatial dark soliton. In contrast to the conventional dark soliton in cubic nonlinear media, the most unique feature of the new soliton can be seen in the twin holes in its intensity profile. With a typical nonlinear material, a way to generate the soliton is proposed. A higher-dimensional extension of it is discussed.