Effect of spark channel length on switching characteristic of laser triggered gas switch

The spark channel generated by focused laser in laser triggered nitrogen gas switch was studied, by using high speed framing camera at the exposure time of 100 ns. Experiments on laser triggered gas switch were carried out with different laser energies and different focuses at the laser wavelength of 266 nm. The delay and jitter of the switch decrease as the laser energy increases. The relationship between the spark channel length of the focused laser and the jitter of the switch was analyzed. When the spark channel length of the focused laser reaches 40% of the total spark gap length, the jitter of the gas switch is at sub-nanosecond level.