Laser ignition of plasma interference switch for microwave pulse extraction from a resonant cavity

Abstract

The influence of laser beam parameters on output pulses of a resonant microwave compressor with laser-triggered plasma switch was investigated. The experimental setup comprised the S-band rectangular waveguide-based cavity and H-plane waveguide tee with the shorted side arm as an interference switch. The system filled with pressurized gas was pumped by a conventional pulsed magnetron, and the Q-switched Nd:YAG laser with the harmonics' unit was used to ignite the discharge in the tee side arm for rapid extraction of the accumulated microwave energy from the cavity. Experiments were conducted with the 2nd (532 nm) and 5th (213 nm) harmonics of the laser radiation frequency, at different directions of the laser beam with respect to the RF electric field, at different levels of light intensity, and with the unfocused and focused laser beams. In the latter case, the laser beam was focused at the center of the tee waveguide cross-section or at the back wall of the tee waveguide.