利用超高速相机，在曝光时间100 ns时，对不同能量下激光在氮气气体开关中形成的火花通道进行拍照，得到了不同焦距下激光波长266 nm时激光火花通道长度与激光能量的关系。开展了激光触发气体火花开关的实验研究，激光触发开关延时、抖动随激光能量的增加而减小。将火花通道长度与激光触发开关的特性进行了分析，气体开关的抖动随着激光火花通道长度的增加而减小，当火花通道沿电极间轴向长度达到开关电极间距40%时，开关的抖动为亚ns量级。

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.