The influence of divergence on the filament length during the propagation of intense ultra-short laser pulses

摘要

We have questioned the conventional criterion, which is the critical power for self-focusing, to predict the stopping position of a filament. Our experimental result suggests that during the filamentation process the plasma induces an additional diffraction of the laser beam. This is another crucial factor that may lead to the termination of the filament even if the power is still much higher than the critical power. This should be taken into account in order to estimate the end of the filament as well as its length.