Parameters of 391 nm lasing from molecular nitrogen ions pumped by a 950 nm femtosecond laser pulse.

The results of experimental studies of spectral, temporal, and spatial self-seed lasing characteristics at the wavelength of 391 nm in pure nitrogen at different values of specific pump power are presented. Pumping was carried out by a femtosecond radiation pulse at the wavelength of 950 nm. The possibility of obtaining lasing pulse duration close to transform-limited (1.83 ps) is presented. It is shown that far-field radiation divergence decreases with increasing lens focal length, and it correlates well with the geometric dimensions of laser plasma.