High spectral energy density supercontinuum generation in fused silica by interfering two femtosecond laser beams

The filaments formed by interference of femtosecond laser beams are distributed over the cross section of the laser beams, which could allow the incident laser pulse to have a relatively high energy and to generate high power supercontinuum (SC) in fused silica. In this paper, two-beam interference induced filamentation and SC in fused silica are experimentally studied. The spectrum of the SC is shown to be sensitive to cross angle and time delay between the two laser pulses. In our experimental conditions, the spectral energy density of the SC emission can reach the order of mu J nm(-1) from 726 to 859 nm and 0.1 mu J nm(-1) from 500 to 700 nm. The interference method provides an alternative and flexible approach to obtain the intense SC generation in condensed optical media.