Impulsive rotational Raman scattering of N2 by a remote "air laser" in femtosecond laser filament

Opt Lett. 2014 Apr 15;39(8):2250-3. doi: 10.1364/OL.39.002250.

Abstract

We report on experimental realization of impulsive rotational Raman scattering from neutral nitrogen molecules in a femtosecond laser filament using an intense self-induced white-light seeding "air laser" generated during the filamentation of an 800 nm Ti:sapphire laser in nitrogen gas. The impulsive rotational Raman fingerprint signals are observed with a maximum conversion efficiency of ∼0.8%. Our observation provides a promising way of remote identification and location of chemical species in the atmosphere by a rotational Raman scattering of molecules.