Faria, CFD;
Rotter, I;
(2002)
High-order harmonic generation in a driven two-level atom: Periodic level crossings and three-step processes.
PHYS REV A
, 66
(1)
, Article 013402. 10.1103/PhysRevA.66.013402.
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Abstract
We investigate high-order harmonic generation in closed systems using the two-level atom as a simplified model. By means of a windowed Fourier transform of the time-dependent dipole acceleration, we extract the main contributions to this process within a cycle of the driving field. We show that the patterns obtained can be understood by establishing a parallel between the two-level atom and the three-step model. In both models, high-order harmonic generation is a consequence of a three-step process, which involves either the continuum and the ground state, or the adiabatic states of the two-level Hamiltonian. The knowledge of this physical mechanism allows us to manipulate the adiabatic states, and consequently the harmonic spectra, by means of a bichromatic driving field. Furthermore, using scaling laws, we establish sharp criteria for the invariance of the physical quantities involved. Consequently, our results can be extended to a broader parameter range, as, for instance, those characteristic of solid-state systems in strong fields.
Type: | Article |
---|---|
Title: | High-order harmonic generation in a driven two-level atom: Periodic level crossings and three-step processes |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1103/PhysRevA.66.013402 |
Publisher version: | http://dx.doi.org/10.1103/PhysRevA.66.013402 |
Language: | English |
Additional information: | ©2002 The American Physical Society |
Keywords: | CYCLIC ORGANIC-MOLECULES, ATTOSECOND PULSE TRAINS, ULTRASHORT LASER-PULSES, STATIC ELECTRIC-FIELD, LANDAU-ZENER MODEL, 2-LEVEL ATOM, QUANTUM-WELLS, AVOIDED CROSSINGS, TEMPORAL PROFILE, IONIZATION |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
URI: | https://discovery-pp.ucl.ac.uk/id/eprint/292055 |
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