title: Harmonic generation from relativistic plasma surfaces in ultrasteep plasma density gradients.
abstract: Harmonic generation in the limit of ultrasteep density gradients is studied experimentally. Observations reveal that, while the efficient generation of high order harmonics from relativistic surfaces requires steep plasma density scale lengths (L(p)/λ < 1), the absolute efficiency of the harmonics declines for the steepest plasma density scale length L(p)→0, thus demonstrating that near-steplike density gradients can be achieved for interactions using high-contrast high-intensity laser pulses. Absolute photon yields are obtained using a calibrated detection system. The efficiency of harmonics reflected from the laser driven plasma surface via the relativistic oscillating mirror was estimated to be in the range of 10(-4)-10(-6) of the laser pulse energy for photon energies ranging from 20-40 eV, with the best results being obtained for an intermediate density scale length.
authors.affiliation: Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Jena, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Rödel
authors.forename: D
authors.initials: D
authors.lastname: an der Brügge
authors.forename: J
authors.initials: J
authors.lastname: Bierbach
authors.forename: M
authors.initials: M
authors.lastname: Yeung
authors.forename: T
authors.initials: T
authors.lastname: Hahn
authors.forename: B
authors.initials: B
authors.lastname: Dromey
authors.forename: S
authors.initials: S
authors.lastname: Herzer
authors.forename: S
authors.initials: S
authors.lastname: Fuchs
authors.forename: A Galestian
authors.initials: AG
authors.lastname: Pour
authors.forename: E
authors.initials: E
authors.lastname: Eckner
authors.forename: M
authors.initials: M
authors.lastname: Behmke
authors.forename: M
authors.initials: M
authors.lastname: Cerchez
authors.forename: O
authors.initials: O
authors.lastname: Jäckel
authors.forename: D
authors.initials: D
authors.lastname: Hemmers
authors.forename: T
authors.initials: T
authors.lastname: Toncian
authors.forename: M C
authors.initials: MC
authors.lastname: Kaluza
authors.forename: A
authors.initials: A
authors.lastname: Belyanin
authors.forename: G
authors.initials: G
authors.lastname: Pretzler
authors.forename: O
authors.initials: O
authors.lastname: Willi
authors.forename: A
authors.initials: A
authors.lastname: Pukhov
authors.forename: M
authors.initials: M
authors.lastname: Zepf
authors.forename: G G
authors.initials: GG
authors.lastname: Paulus