Plasma luminescence from femtosecond filaments in air: evidence for impact excitation with circularly polarized light pulses.
Filaments produced in air by intense femtosecond laser pulses emit UV luminescence from excited N(2) and N(2)(+) molecules. We report on a strong dependence at high intensities (I≥1.4×10(14)  W/cm(2)) of this luminescence with the polarization state of the incident laser pulses. We attribute this effect to the onset of new impact excitation channels from energetic electrons produced with circularly polarized laser pulses above a threshold laser intensity.
Laboratoire d'Optique Appliquée, ENSTA/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau F-91762, France.
Sergey
S
Mitryukovskiy
Laboratoire d'Optique Appliquée, ENSTA/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau F-91762, France.
Yi
Y
Liu
Laboratoire d'Optique Appliquée, ENSTA/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau F-91762, France.
Pengji
P
Ding
Laboratoire d'Optique Appliquée, ENSTA/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau F-91762, France.
Aurélien
A
Houard
Centre de Physique Théorique, Ecole Polytechnique, CNRS, Palaiseau F-91128, France.
Arnaud
A
Couairon
Laboratoire d'Optique Appliquée, ENSTA/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau F-91762, France.
André
A
Mysyrowicz