Temporal behavior of air lasing by molecular nitrogen ions

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 λ=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. •Lasing pulse duration was measured by using streak camera with high resolution.•The delay between the lasing pulse maximum and pumping was found.•Lasing had greater power and directionality than that of spontaneous emission.•Supercontinuum propagated in the form of hollow cone.