ИСТИНА

The results of experimental and numerical investigation of single and multiple pulse filamentation in LiF at the spectral range from 800 nm to 3500 nm are presented. By the laser coloration method it is revealed that in the case of single pulse filamentation in the normal GVD spectral range the length of the high intensity light field is not more than 100 mcm. At anomalous GVD, when LB arises, this length increases up to 600 mcm with laser wavelength increasing to 3500 nm. In the multiple pulse filamentation regime a waveguide emerges which enlarges the LB path length up to 2.5mm. It is revealed that LB is a short-lived object which changes its diameter and light field amplitude on the propagation along the path length. In the multiple pulse regime due to refractive index periodic modulation, induced by LBs in a waveguide, spectral components arise in the supercontinuum visible range, the angular divergence of which increases with increasing wavelength.