title: Recollision-Induced Superradiance of Ionized Nitrogen Molecules.
abstract: We propose a new mechanism to explain the origin of optical gain in the transitions between the excited and ground states of the ionized nitrogen molecule following irradiation of neutral nitrogen molecules with an intense ultrashort laser pulse. An efficient transfer of population to the excited state is achieved via field-induced multiple recollisions. We show that the proposed excitation mechanism must lead to a superradiant emission, a feature that we confirm experimentally.
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 boulevard des Maréchaux, 91762 Palaiseau Cedex, France.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 boulevard des Maréchaux, 91762 Palaiseau Cedex, France.|School of Nuclear Science and Technology, Lanzhou University, 730000 Lanzhou, China.
authors.forename: Pengji
authors.initials: P
authors.lastname: Ding
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 boulevard des Maréchaux, 91762 Palaiseau Cedex, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lambert
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 boulevard des Maréchaux, 91762 Palaiseau Cedex, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Houard
authors.affiliation: Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS UMR 5107, Talence 33405, France.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tikhonchuk
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 828 boulevard des Maréchaux, 91762 Palaiseau Cedex, France.
authors.forename: André
authors.initials: A
authors.lastname: Mysyrowicz