Transition matrix elements derived previously (J Gao et al 1998 Phys. Rev. Lett. 81 1833) from QED theory to describe high-order harmonic generation in intense optical fields are modified for elliptically polarized fields and compared with semiclassical theory and recent experimental studies of harmonic polarization characteristics. Calculations are in agreement with published data for Ne and Ar, including measurements of the components of the harmonic yield that are parallel or transverse to the major axis of the polarization ellipse for the driving optical field. The results confirm that preserving discrete photoelectron energies and incorporating two to three above-threshold ionization orders into the calculations account for the data. Also, the calculations demonstrate that the Volkov → Volkov state transition matrix element is capable of describing the polarization characteristics of the harmonics.
|Number of pages
|Journal of Physics B: Atomic, Molecular and Optical Physics
|Published - Sep 14 1999
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics