Influence of optical angular momentum on filamentation of 800 nm femtosecond laser pulses in fused silica

Filamentation of femtosecond laser pulse in optical vortex on wavelength 800 nm in fused silica is numerically studied. Spatio-temporal intensity distributions, fluence distributions and frequency-angular spectra for optical vortex and circular beam are obtained. It is shown that filamentation in optical vortex may tend to formation of stable cylindrical structure, which length is greater than in linear case. Parameters of this structure are presented. Comparative analysis with circular beam is done, estimations of energy transformation into stokes and antistokes spectral domains are calculated.