Filamentation of collimated Ti:sapphire-laser pulses in water

Abstract

ABSTRACT The results of experimental studies of the spatial characteristics of multiple filamentation terawatt femtosecond Ti:Sa-laser in water are presented. With an increase in initial power laser pulses increases the number of filaments, the length of the field is increased filamentation and reducing the length of the filaments have been shown. The distribution of thefilaments in the longitudinal direction of the field of multiple filamentation has a maximum cross-sectional filament isshifted from the center to the periphery of the beam at the end region of filamentation. The minimum diameter of thebeam on the track corresponds to the position of the maximum number of filaments. After the point of maximum impulse essentially loses energy in the initial direction of propagation. Upon reaching the pulse power 2 10 4 P cr of multiple filamentation area is formed of a hollow cone, the apex directed to the radiation source.Keywords: laser radiation filamentation, femtosecond pulse, the liquid The problems of nonlinear optics of femtosecond atmosphere and ocean interesting from the point of view of thefundamental issues and promising for practical use is the effect of filamentation of laser beams. [1] In [2-4] performedexperimental studies of filamentation in the water, but as a rule, they firmly focused radiation in the volume of fluid thatwas determined insufficient for collimated beams length of the track. Theoretical studies were primarily singlefilamentation cases [5,6], or as tightly focused beams [2]. This report presents the results of an experimental study of thespatial structure and quantitative characteristics of the field of multiple filamentation (FMF) of collimated laser beams in the water. Scheme of the experiment is shown in Figure 1.