title: Two-color interferometer for the study of laser filamentation triggered electric discharges in air.
abstract: We present a space and time resolved interferometric plasma diagnostic for use on plasmas where neutral-bound electron contribution to the refractive index cannot be neglected. By recording simultaneously the plasma optical index at 532 and 1064 nm, we are able to extract independently the neutral and free electron density profiles. We report a phase resolution of 30 mrad , corresponding to a maximum resolution on the order of 4×10(22) m(-3) for the electron density, and of 10(24) m(-3) for the neutral density. The interferometer is demonstrated on centimeter-scale sparks triggered by laser filamentation in air with typical currents of a few tens of A.
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Point
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: Yohann
authors.initials: Y
authors.lastname: Brelet
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: Leonid
authors.initials: L
authors.lastname: Arantchouk
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Carbonnel
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Prade
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: André
authors.initials: A
authors.lastname: Mysyrowicz
authors.affiliation: Laboratoire d'Optique Appliquée - ENSTA ParisTech, Ecole Polytechnique, CNRS - 828 boulevard des Maréchaux, 91762 Palaiseau, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Houard