Measurements of Air Breakdown and Scaling to Microwaves Using 193 nm Focused Laser Radiation

We report the measurements and analysis of air breakdown processes by focusing 193 nm, 200 mJ, 10 MW high power UV laser radiation on to a 10 - 20 mum spot size that produces laser power densities up to 10¹² -10¹³ W/cm² , well above the threshold power flux for air ionization. The breakdown threshold is measured and compared with classical and quantum theoretical models. A universal scaling analysis of these results allows one to predict some aspects of high power microwave breakdown based on measured laser breakdown observations.