Multiphoton ionization in dielectrics: comparison of circular and linear polarization.
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.
Temnov
V V
VV
Institut für Experimentelle Physik, Universität Duisburg-Essen, 47048 Duisburg, Germany.
Sokolowski-Tinten
K
K
Zhou
P
P
El-Khamhawy
A
A
von der Linde
D
D