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

摘要

We report on experimental realization of impulsive rotational Ramanscattering from neutral nitrogen molecules in a femtosecond laser filamentusing an intense self-induced white-light seeding "air laser" generated duringthe filamentation of an 800 nm Ti: Sapphire laser in nitrogen gas. Theimpulsive rotational Raman fingerprint signals are observed with a maximumconversion efficiency of ~0.8%. Our observation provides a promising way ofremote identification and location of chemical species in atmosphere byrotational Raman scattering of molecules.