title: Experimental evidence of above-threshold photoemission in solids.
abstract: Nonlinear photoemission from a silver single crystal is investigated by femtosecond laser pulses in a perturbative regime. A clear observation of above-threshold photoemission in solids is reported for the first time. The ratio between the three-photon above-threshold and the two-photon Fermi edges is found to be 10(-4). This value constitutes the only available benchmark for theories aimed at understanding the mechanism responsible for above-threshold photoemission in solids.
authors.affiliation: Istituto Nazionale per la Fisica della Materia and Dipartimento di Matematica e Fisica, Università Cattolica, I-25121 Brescia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Banfi
authors.forename: Claudio
authors.initials: C
authors.lastname: Giannetti
authors.forename: Gabriele
authors.initials: G
authors.lastname: Ferrini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Galimberti
authors.forename: Stefania
authors.initials: S
authors.lastname: Pagliara
authors.forename: Daniele
authors.initials: D
authors.lastname: Fausti
authors.forename: Fulvio
authors.initials: F
authors.lastname: Parmigiani