The Dynamics of Laser-Driven Ionisation in High-Voltage Circuit Switching

This study explores the use of laser-induced ionisation for triggering high-voltage (HV) discharges offers a precise, non-invasive alternative to conventional spark gap methods. Conducted at the HiLASE Centre using an advanced picosecond laser system, the research investigates how laser parameters — including wavelength, pulse energy, and irradiance — affect air breakdown voltage and discharge delay. Experimental results show that focused ultrafast laser pulses can significantly reduce the breakdown voltage, with reductions up to 30%, depending on wavelength and gap distance. Moreover, the delay between laser pulse and breakdown decreases with higher irradiance, particularly at lower voltages where exponential delay trends were observed. These findings confirm the efficacy of quantum ionisation in air and demonstrate the potential of laser-assisted triggering for fast and reliable HV switching. The ability to tailor breakdown characteristics through laser control opens new possibilities for advanced plasma applications, precision circuit protection, and high-speed switching technologies.