Temporal behavior of air lasing by molecular nitrogen ions

摘要

The experimental results of studying the temporal and spectral characteristics of air lasing of a first negative system of molecular nitrogen ions in laser plasma are presented here. Pumping was carried out by femtosecond laser pulse with a wavelength of 950 nm. By using streak camera, the pulse duration of lasing at lambda = 428 nm (1.15 ps, FWHM) was measured. It was close to transform-limited (1 ps). It is shown that there is a delay (5.6 ps) of lasing pulse maximum with respect to the pumping. Lasing has higher directionality and shorter duration compared with spontaneous emission.