title: Multiphoton ionization in dielectrics: comparison of circular and linear polarization.
abstract: Ionization mechanisms in bulk dielectrics irradiated by single intense 50-fs-laser pulses are investigated by ultrafast time-resolved imaging interferometry. Polarization-sensitive 6-photon ionization is shown to be the dominant ionization mechanism in fused silica and sapphire at intensities around 10 TW/cm2. For both materials the cross sections of 6-photon ionization are found to be significantly higher for linear polarization than for circular. Our experimental results corroborate an earlier theoretical prediction on the dominance of linear polarization in high-order multiphoton ionization.
authors.affiliation: Institut für Experimentelle Physik, Universität Duisburg-Essen, 47048 Duisburg, Germany.
authors.forename: V V
authors.initials: VV
authors.lastname: Temnov
authors.forename: K
authors.initials: K
authors.lastname: Sokolowski-Tinten
authors.forename: P
authors.initials: P
authors.lastname: Zhou
authors.forename: A
authors.initials: A
authors.lastname: El-Khamhawy
authors.forename: D
authors.initials: D
authors.lastname: von der Linde