Phase- and helicity-dependent effects in three-color ionization

Abstract

Abstract:We study the two-photon ionization of the hydrogen atom from its ground state by a three-color electromagnetic field consisting of a superposition of an IR laser and two of its consecutive odd harmonics of order 2p − 1 and 2p + 1, with p a positive integer and constant relative phase difference. The ionization process due to the net absorption of the energy 2phω (ω being the IR laser frequency) is considered. The influence of phase difference and helicity on the azimuthal angular distribution of the ejected photoelectrons is illustrated in the case in which the two harmonics have identical polarizations. Phase effect on the alignment of the differential ionization rate is also investigated.

Photoelectron spectra in strong-field ionization by a high frequency field

“…Perelomov and Popov were the first to study theoretically ionization of an atom by multi-color laser radiation [20] within the imaginary-time method [21]. Afterwards, a broad variety of perturbative [22,23,24,25] as well as non-perturbative results [26,27,28,29,30,31,32] has been obtained. In addition, extensive numerical investigations have also been performed [33,34,35,36,37,38,39,40].…”