Two-dimensional type I quadratic spatial solitons in KNbO_3 near noncritical phase matching

Experiments on the properties of quadratic, two-dimensional spatial soliton properties in ${\mathrm{KNbO}}_3$ near and at noncritical phase matching (NCPM) are reported. The NCPM geometry leads to unique features such as a large angular bandwidth for soliton generation, weak dependence of soliton composition on intensity and incidence angle, and unique multisoliton-generation properties.