High-voltage electrical discharges induced by an ultrashort-pulse UV laser system

Using a femtosecond UV laser source (248.6 nm), we have conducted studies on large-gap laser-induced electrical discharges. Parameters such as pressure, lens selection, focal position and laser energy were investigated. We also present an experimental technique that allows the measurement of ionization cross-sections at atmospheric pressures. Spectroscopic analysis of the laser plasma and discharge are also presented. Prospects and conditions leading to a discharge over tens of metres, with dual UV and IR laser pulses, are discussed.