Regular Article

Excitation of nitrogen molecular ions in a strong laser field by electron recollisions

¹ Centre Lasers Intenses et Applications, University of Bordeaux-CNRS-CEA, 33405 Talence, France
² University Laval, Quebec, QC GV 0A6, Canada
³ Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, 200093 Shanghai, P.R. China
⁴ Laboratoire d’Optique Appliquée, ENSTA ParisTech, CNRS, Ecole Polytechnique, University Paris-Saclay, 91762 Palaiseau, France

^a e-mail: tikhonchuk@u-bordeaux.fr

Received: 10 July 2017
Received in final form: 5 September 2017
Published online: 16 November 2017

Abstract

A semiclassical model of electron rescattering in a strong laser field is applied to the evaluation of the probability of nitrogen molecular ion excitation. Depending on the ionization phase, a group of electrons oscillate around the parent ion for several laser periods and rescatter at large angles. The effect of ion attraction enhances significantly the probability of ion excitation by electron–ion collisions. The total probability of ion transfer from ground to excited ionic molecular state and the corresponding dipolar moment are evaluated for typical laser filament parameters.