Low-energy structures in strong field ionization revealed by quantum orbits

• Published in: Physical review letters 2010-12, Vol.105 (25), p.253002-253002, Article 253002
• Main Authors: Yan, Tian-Min, Popruzhenko, S V, Vrakking, M J J, Bauer, D
• Format: Article
• Language: English
• Subjects: APPROXIMATIONS; ATOMIC AND MOLECULAR PHYSICS; ATOMS; CALCULATION METHODS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DIFFERENTIAL EQUATIONS; ELECTRON SPECTROSCOPY; EQUATIONS; INCLUSIONS; IONIZATION; LASERS; MATHEMATICAL SOLUTIONS; ORBITS; PARTIAL DIFFERENTIAL EQUATIONS; PHOTOELECTRON SPECTROSCOPY; PULSES; SCHROEDINGER EQUATION; SEMICLASSICAL APPROXIMATION; SPECTROSCOPY; TIME DEPENDENCE; TRAJECTORIES; WAVE EQUATIONS
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.105.253002

Experiments on atoms in intense laser pulses and the corresponding exact ab initio solutions of the time-dependent Schrödinger equation (TDSE) yield photoelectron spectra with low-energy features that are not reproduced by the otherwise successful work horse of strong field laser physics: the "strong field approximation" (SFA). In the semiclassical limit, the SFA possesses an appealing interpretation in terms of interfering quantum trajectories. It is shown that a conceptually simple extension towards the inclusion of Coulomb effects yields very good agreement with exact TDSE results. Moreover, the Coulomb quantum orbits allow for a physically intuitive interpretation and detailed analysis of all low-energy features in the semiclassical regime, in particular, the recently discovered "low-energy structure" [C. I. Blaga, Nature Phys. 5, 335 (2009) and W. Quan, Phys. Rev. Lett. 103, 093001 (2009).