Complete suppression of N$_2$ lasing by the nonadiabatic molecular alignment effect in femtosecond filaments
Résumé
The nonadiabatic molecular alignment effect is commonly found helpful in enhancing nonlinear processes such as high-order harmonics and strong-field ionization. In this work, an opposite phenomenon is observed, in which the nonadiabatic molecular alignment effect prepared with a linearpolarized prepulse strongly suppresses the generation of N$_2$ lasing induced by circularly-polarized 800 nm femtosecond laser pulse in filament plasma. The presence of a weak prepulse periodically suppresses the lasing at each revival timing of the rotational wave packet of the N$_2$ molecule. The underlying mechanism of the lasing signal suppression is attributed to sudden change of the polarization ellipticity of the pump laser pulse. Theoretical simulations by numerically solving the time-dependent Schrödinger equation with the molecular alignment effect included confirm sensitive changes of the polarization ellipticity of the pump laser at every alignment revival, which largely supports our interpretation.
Domaines
Optique [physics.optics]Origine | Fichiers produits par l'(les) auteur(s) |
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