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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:25 |
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Conference: Bucharest University Faculty of Physics 2001 Meeting
Section: Statistical Physics and Quantum Mechanics
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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