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 10TW/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.
- Publication:
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Physical Review Letters
- Pub Date:
- December 2006
- DOI:
- Bibcode:
- 2006PhRvL..97w7403T
- Keywords:
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- 78.47.+p;
- 32.80.Rm;
- 42.65.-k;
- 72.20.Jv;
- Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter;
- Multiphoton ionization and excitation to highly excited states;
- Nonlinear optics;
- Charge carriers: generation recombination lifetime and trapping