Supercontinuum generation in filamentation of femtosecond laser pulse in fused silica

Abstract

The Supercontinuum (SC) generation during femtosecond laser pulse filamentation with various central wavelengths in fused silica is investigated by numerical solution of nonlinear Schroedinger equation. Material dispersion of the medium is considered due to Sellmeier formula. Nonmonotonic dependence of spectral intensity on wavelength in anti-Stokes wing for anomalous group velocity dispersion (GVD) region (λ₀ = 1900 nm) was found. There is a local minimum in SC spectrum from 800 nm to 1200 nm, and there is also a local maximum in SC spectrum from 400 nm to 700 nm. We suppose such modification of pulse spectrum during filamentation process to be caused by interference modulation of SC spectrum in presence of anomalous GVD.