Femtosecond multiple filamentation of an optical vortex in the mid-IR wavelength range in fused silica and fluorides
Autor: | S.A. Shlenov, V.O. Kompanets, A.A. Dergachev, V.P. Kandidov, S.V. Chekalin, F.I. Soifer |
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Rok vydání: | 2022 |
Předmět: | |
Zdroj: | Quantum Electronics. 52:322-327 |
ISSN: | 1468-4799 1063-7818 |
Popis: | The results of experimental and theoretical study of the self-action of femtosecond optical vortices in the region of anomalous group velocity dispersion in fused silica and fluorides are presented. Multiple filamentation of an axially asymmetric annular beam with a phase dislocation of topological charge m = 1 at a wavelength of 1800 nm in a LiF crystal is investigated. It is found that for the experimentally recorded intensity profile of a vortex beam with two maxima on the diameter, the critical self-focusing power is approximately two times larger than the critical power of a unimodal Gaussian beam. In pulses with supercritical power in the vicinity of the intensity maxima, two coupled filaments, separated by a phase dislocation, are formed on the annular profile of the optical vortex, which prevents energy exchange during their formation. The length of vortex-beam plasma channels in a single pulse is found to be about 300 μm at a diameter of about 2 μm, which is close to the characteristics of plasma channels in a Gaussian beam. |
Databáze: | OpenAIRE |
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