Long-range third-harmonic generation in air using ultrashort intense laser pulses

The generation of a powerful third-harmonic pulse in atmospheric air has been controlled over long-distance propagation using divergent and negatively chirped fundamental pulses. The cofilamentation of the high-intensity fundamental and third-harmonic pulses was observed over long propagation distance using the Lidar technique. The high peak intensity and the extremely broad spectral content generated by both fundamental and third-harmonic pulses imply promising applications for atmospheric remote sensing of pollutants and bioaerosols