Evaluation of the characteristics of the domain of multiple filamentation of femtosecond laser pulses in air based on the single filamentation model
A.A. Zemlyanov, Yu.E. Geints, O.V. Minina
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: фемтосекундные лазерные импульсы, воздух, самофокусировка, филаментация, дифракционно-лучевая трубка, femtosecond laser pulses, air, self-focusing, filamentation, diffraction-beam tube
Abstract
Characteristics of the multiple filamentation domain in air are estimated on the basis of the numerical solution of the nonlinear Schrödinger equation in the single filamentation problem statement. The method of diffraction-beam tubes was used to describe the single filamentation of laser pulses. The effectiveness of this method for interpreting experimental results and predicting effects is shown, which is important when planning experiments. The characteristic size of small-scale intensity inhomogeneities in the laser centimeter-radius beam profile, which form a multiple filamentation domain for femtosecond pulses, is shown to be several millimeters. An increase in the original laser beam radius during telescoping increases the sizes of the initial small-scale intensity irregularities, which increases the filamentation start distance. An increase in initial beam power contributes to the elongation of the filaments and increases their number.
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