Numerical simulations of filamentation of synthesized femtosecond coronal laser beams in air
Yu.E. Geints, A.A. Zemlyanov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: self-focusing, filamentation, ultra-short laser radiation, synthesized beams
Abstract
Theoretical aspects of nonlinear propagation in air under filamentation of high-power ultrashort laser radiation with coronalike transverse intensity distribution are theoretically considered. A coronal intensity profile is assumed to be formed by incoherent superposition of several emitting sub-apertures arranged into a ring. Using the numerical solution to the time-averaged nonlinear Schrödinger equation, the transformations along an optical path of the intensity profile of the synthesized beams by varying the number and power of the partial emitters composing them are investigated. We show that the synthesized beams of coronal profile have a number of advantages from the point of view of control over the filamentation region. Particularly, by changing the number and geometric size of the individual subapertures it is possible to significantly delay the beginning of filamentation of the whole beam and increase the distance of its existence in comparison with beams of traditional unimodal profile (Gaussian, plateau-shaped).
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