We propose a new mechanism/scheme to explain the ultrafast population inversion of molecular ions which takes place in a time scale comparable to the femtosecond laser pulse. The nonlinear pumping process including the pump photons and the self-generated harmonic photons of the pump laser would be responsible for building up population inversion to realize remote molecule lasers in femtosecond laser filaments in gases. It is shown that the remote laser emissions in molecular ions of gases may be a universal process in the femtosecond laser filament.
© 2013 Chinese Optics Letters
(140.0140) Lasers and laser optics : Lasers and laser optics
(190.0190) Nonlinear optics : Nonlinear optics
(300.0300) Spectroscopy : Spectroscopy
(320.0320) Ultrafast optics : Ultrafast optics
See Leang Chin, Huailiang Xu, Ya Cheng, Zhizhan Xu, and Kaoru Yamanouchi, "Natural population inversion in a gaseous molecular filament," Chin. Opt. Lett. 11, 013201- (2013)