Effects of Raman Delayed Kerr Response on Ultra-short Femtosecond Pulses Propagating in Air

摘要

The effects of Raman delayed Kerr response on the nonlinear refractive index,self-focusing,self-guided filament and supercontinuum generation are studied,basing on the propagation model of ultrashort femtosecond laser pulses in air. The results of numerical simulation indicate Raman delayed response lowers the maximal nonlinear refractive index,moves the peak value to the rear of the pulse and reduces the self-focusing in the front of the pulse. Also, in the presence of Raman delayed Kerr response,the effect of self-focusing is weakened and the stability of a filament is strengthened.Effects of Raman delayed Kerr response also show in a frequency shift from shorter to longer wave components in supercontinuum generation.