Continuous-wave self-focusing and self-trapping of light in artificial Kerr media

Artificial Kerr media made from liquid suspensions of submicrometer particles were used as a new type of nonlinear medium for observing cw self-focusing and self-trapping of laser beams. Self-trapping of TEM(00)-mode beams and higher-order TEM(01)- and TEM(01)* -mode beams were investigated. Saturation-free operation down to filament diameters of ~2 microm was observed. The independence of the critical power for self-trapping on the beam diameter in the unsaturated regime was confirmed for the first time to our knowledge. Values of the nonlinear coefficient were determined for a range of particle diameters from 0.038 to 0.234 microm.