Development of a laser-triggered film switch for nanosecond rectangular pulse generator

A rectangular pulse generator plays an important role in the calibration of impulse measurement as well as the investigation into electromagnetic pulse effect. In addition, the characteristics of an output switch have a direct impact on the generator's output waveform. Following the basic requirements for the switch in a rectangular generator, this paper proposes a new type of laser-triggered film switch with a compact structure and high repeatability. The mechanical structure and operating mechanism of this switch have been elaborated. To verify the feasibility of this switch model, the irradiation experiments were carried out to study the interaction between the laser and the film, and the inductance of the switch has been estimated. Then, to test the characteristics of the switch, a Blumlein rectangular pulse generator based on this switch has been constructed. The experiment results show that the generator worked well in consecutive jobs and had a wild adjustable amplitude range from 2 kV to 10 kV, with a minimum rise-time of less than 1 ns. The effect of the laser loophole and the thickness of the film on the switch have also been investigated. Finally, the plasma developing process of the laser-triggered film switch has been discussed.