Multiphoton ionization of helium under uv radiation: Role of the harmonics

Journal Article · Fri Dec 15 04:00:00 EST 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.063410· OSTI ID:20976503

Nikolopoulos, L A. A.; Lambropoulos, P ^[1]

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1. Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, University of Aarhus, 8000 Arhus C (Denmark)

We present a quantitative theory with detailed calculations pertaining to multiphoton ionization of helium under moderately strong uv radiation of photon energy 13 eV. Employing both, the nonperturbative solution of the time-dependent Schroedinger equation, as well as perturbation theory, we obtain detailed results for all processes expected to be of quantitative relevance within the range of intensities and pulse durations in this work, which have been chosen so as to match the conditions of a recent experiment on exactly this problem [T. Laarman et al., Phys. Rev. A 72, 023409 (2005)]. The conclusion, in connection with the experimental data, which our results lead to is that, without the presence of the second harmonic of the fundamental in the radiation, it is impossible to reconcile the reported observations with fundamental features of the processes involved. A more general conclusion seems to be that the presence of these harmonics, even at intensities less than 1% of that of the fundamental, are apt to produce profound side effects that will mask multiphoton processes by the fundamental.

• OSTI ID: 20976503
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
EV RANGE 10-100
HARMONICS
HELIUM
MATHEMATICAL SOLUTIONS
MULTI-PHOTON PROCESSES
PERTURBATION THEORY
PHOTOIONIZATION
PHOTON-ATOM COLLISIONS
PHOTONS
PULSES
RESPIRATORS
SCHROEDINGER EQUATION
TIME DEPENDENCE
ULTRAVIOLET RADIATION