title: Small atomic displacements recorded in bismuth by the optical reflectivity of femtosecond laser-pulse excitations.
abstract: Subtle atomic motion in a Bi crystal excited by a 35 fs-laser pulse has been recovered from the transient reflectivity of an optical probe measured with an accuracy of 10(-5). Analysis shows that a novel effect reported here-an initial negative drop in reflectivity-relates to a delicate coherent displacement of atoms by the polarization force during the pulse. We also show that reflectivity oscillations with a frequency coinciding with that of cold Bi are related to optical phonons excited by the electron temperature gradient through electron-phonon coupling.
authors.affiliation: Laboratoire d'Optique Appliquée, ENSTA/Ecole Polytechnique, Palaiseau, France. davide.boschetto@ensta.fr
authors.forename: D
authors.initials: D
authors.lastname: Boschetto
authors.forename: E G
authors.initials: EG
authors.lastname: Gamaly
authors.forename: A V
authors.initials: AV
authors.lastname: Rode
authors.forename: B
authors.initials: B
authors.lastname: Luther-Davies
authors.forename: D
authors.initials: D
authors.lastname: Glijer
authors.forename: T
authors.initials: T
authors.lastname: Garl
authors.forename: O
authors.initials: O
authors.lastname: Albert
authors.forename: A
authors.initials: A
authors.lastname: Rousse
authors.forename: J
authors.initials: J
authors.lastname: Etchepare