Long-term stability and laser-induced damage resistance of optical components in the UV region are critical for enhancing their performance in UV high-power laser applications. This study evaluates the laser-induced damage threshold (LIDT) of commercially available UV optical windows with anti-reflective (AR) coating, produced through various coating techniques and designed for high-power lasers. A third-harmonic (343 nm) wavelength with good beam quality was generated in the picosecond regime to investigate the LIDT of optical components. The LIDT for each sample was measured under controlled conditions and compared based on their coating techniques. The sample coated with Al₂O₃/SiO₂ through ion beam sputtering has the best LIDT value, of 0.6 J/cm², among the tested samples, based on the hundred-thousand-pulses methodology. The damage threshold curve and the corresponding damage morphology are discussed in detail, and these findings provide insights into the durability and susceptibility of UV optics for advanced laser systems available in the market.

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.