Abstract

We have studied a new type of electric discharge triggered in air by intense femtosecond IR laser pulses. When propagating in atmosphere, such pulses self-organize in the form of filaments, leaving in their wake a thin plasma column with uniform density along the axis. This plasma column can act as a trigger for electric discharges. The discharge occurs under reduced applied voltage and follows the path of the self-guided laser pulse (see figure). Its onset is reproducible, but occurs with a measurable delay. This is to be contrasted with the typical discharge initiated by a non-uniform laser-produced plasma, for which the onset of the discharge fluctuates considerably from shot to shot.

© 2000 IEEE