Multiple filamentation of collimated laser radiation in water and glass

Results of an experimental study of spatial parameters of the region of multiple filamentation of gigaand terawatt pulses of a Ti:Sapphire laser in glass and water are described. The pulse-power dependencies of the coordinates of the filamentation region, the number of filaments, their distribution along the laser beam axis, and the mean length of the filaments are presented. It is shown that the spatial parameters of the filamentation region are qualitatively similar in water and glass. It is found that the number of filaments along the region of multiple filamentation is a unimodal distribution. When increasing the radiation power, the length of individual filaments in the region of multiple filamentation is reduced, and their diameters are quasi-constant at all power values implemented in the experiment. When attaining a certain power of laser pulses with a Gaussian energy-density distribution, the filamentation region takes the shape of a hollow cone with the apex directed to the radiation source.