Air ultraviolet laser excited by high-power microwave pulses

Lasing in atmospheric air excited by high-power nanosecond microwave pulses was observed and investigated. Stimulated emission was observed as a result of transitions in N₂ at wavelengths λ = 315.8, 337.1, and 357.7 nm and resonator-free amplification of spontaneous radiation. The forward and backward laser fluxes differed by a factor exceeding 10 demonstrating that a traveling wave configuration was established. The optimal air pressure was 38 Torr. In principle, it should be possible to construct a laser using free–localized discharge in air excited by crossing laser beams.