Picosecond triggering of a laser-triggered spark gap

Abstract

The characteristics of laser-triggered spark gaps, initiated by a switched-out pulse of about 7 ps from a model-locked Nd: glass laser system, are investigated. The formation time delay of breakdown across the gap can be of the order of 1 ns and is found to increase as the gap voltage is reduced. Comparison with spark gaps triggered by Q-spoiled nanosecond laser pulses is made. Finally, a comparison of the agreement between the experimental results and theory suggests that the initiation of gap breakdown is due to the production of only a few free electrons from the electrode surface on which the laser beam is focused.