Femtosecond laser guiding of a high-voltage discharge and the restoration of dielectric strength in air and nitrogen

The use of a low energy, high peak intensity (>100 TW/cm2) femtosecond laser pulse is investigated for guiding and control of a sub-microsecond high voltage discharge. Study of the laser induced plasma channel and measurements of the field required for breakdown in air and nitrogen at atmospheric pressure are presented. Direct imaging of the dynamics of the discharge breakdown shows effective laser guiding. The effectiveness of laser guiding is shown to be critically dependent on the laser focusing geometry, timing, and location relative to the electrodes.