Effect of rotational wave packets on the stimulated emission of nitrogen with light filament

• Forward and side emission of nitrogen ion at 428 nm by 800 nm ultrashort pulses.
• Forward emission of circularly polarized light is smaller than linear.
• We measure the rotational distribution in forward emission in P and R branches.
• Circular polarized with orbital angular momentum results stronger forward emission.
• We see a correlation between higher rotational “J” state and high emission of 428.

We measure forward emission of the nitrogen ion excited by light filaments at 800 nm. The radiation strongly depends on light polarization and orbital angular momentum. In all cases the rotational distribution of nitrogen molecules plays an essential role in the 428 nm stimulated emission.