title: Dynamics of the critical surface in high-intensity laser-solid interactions: modulation of the XUV harmonic spectra.
abstract: The generation of harmonics from the interaction of an intense (I>or=10(18) W cm(-2)) laser with a solid surface is investigated. Modulation of the harmonic emission spectrum with a periodicity of 2 to 4 harmonics is observed at higher laser intensities. A similar modulation is predicted by a particle-in-cell simulation. The modulation is shown to be caused by the higher modes of oscillation of the critical surface during the interaction. As a result, the dynamics of the critical surface can be inferred from the shape of the harmonic spectrum.
authors.affiliation: The Blackett Laboratory, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BZ, United Kingdom.
authors.forename: I
authors.initials: I
authors.lastname: Watts
authors.forename: M
authors.initials: M
authors.lastname: Zepf
authors.forename: E L
authors.initials: EL
authors.lastname: Clark
authors.forename: M
authors.initials: M
authors.lastname: Tatarakis
authors.forename: K
authors.initials: K
authors.lastname: Krushelnick
authors.forename: A E
authors.initials: AE
authors.lastname: Dangor
authors.forename: R M
authors.initials: RM
authors.lastname: Allott
authors.forename: R J
authors.initials: RJ
authors.lastname: Clarke
authors.forename: D
authors.initials: D
authors.lastname: Neely
authors.forename: P A
authors.initials: PA
authors.lastname: Norreys