SELF-FOCUSED LIGHT-PROPAGATION IN A FULLY SATURABLE MEDIUM - EXPERIMENT

We report observations of self-focusing and filamentation, i.e., the f ormation of one or more self-trapped beams, of similar to 3 ns laser p ulses in strontium (Sr) vapor. The experimental arrangement consists o f a Sr vapor cell and a pulsed neodymium-doped yttrium aluminum garnet pumped dye laser tuned to the blue of the 461 nm transition in Sr. Th e spatial intensity distribution of individual self-focused beams has been measured at the exit window of a vapor cell by using a magnifying lens and video camera. Measurements of power dependence, spatial dist ributions, and scaling behavior for filament formation are in good agr eement with theory over a wide range of vapor densities, laser detunin gs, and laser powers.