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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:23 |
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Conference: Bucharest University Faculty of Physics 2001 Meeting
Section: Theoretical Physics and Applied Mathematics
Title:
HARMONIC GENERATION IN INTENSE EXTERNAL FIELD
Authors:
Diana Isvoranu, M. Dondera
Affiliation:
Faculty of Physics, University of Bucharest
E-mail
Keywords:
Abstract:
A charged particle in an accelerated motion emits electromagnetic radiation. For an atom in interaction with a laser field, the emission of radiation having the frequency a multiple (odd for atomic systems with inversion symmetry) of the external field frequency is greatly enhanced. This process, called harmonic generation (HG), has attracted a considerable interest (experimental and theoretic) over the years.
The HG theoretical study implies two stages, a first one describing the single-atom response to the laser field, and a second one to characterize the macroscopic response of the medium (the so called phase-matching conditions).
In our paper we consider only the single-atom response, for the case of an 1D "atom": an electron in motion along a line, in a static potential, exposed to a pulse of an oscillant electric field. The physical quantity we analyze is the emitted radiation spectrum, obtained by a known procedure, consisting in the numerical integration of the Schrodinger equation for the pulse duration, starting from an initial stationary state (usually taken as the ground state), and the determination of the spectrum from the Fourier transform of the average dipole moment.
We present numerical results for static potentials having a short range (Gaussian) and a long range ("soft" Coulomb), which illustrate the influence of various parameters of the pulse (profile, frequency, peak amplitude and duration) over the spectrum.
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