Remote triggering of air-gap discharge by a femtosecond laser filament and postfilament at distances up to 80 m

We experimentally observed laser-induced remote high-voltage discharge triggering between two needle electrodes with half-a-cm spacing. The discharge was initiated by a 744-nm, 90-fs, 6-mJ laser pulse undergoing filamentation in air. For the direct voltage below the self-breakdown threshold, triggering of air-gap discharge was synchronized with a 10-Hz laser repetition rate and occurred between 40 and 80 m of the propagation path. No discharge guiding was observed. The experimentally registered and simulated remote triggering probability was above 80% in the range of 45-60 m from laser output and about 50% in the range of 60-80 m. The probability decreases as the postfilament hot spot diverges with a simultaneous increase in stochastic laser beam wandering.