94 research outputs found
Steady state of atoms in a resonant field with elliptical polarization
We present a complete set of analytical and invariant expressions for the
steady-state density matrix of atoms in a resonant radiation field with
arbitrary intensity and polarization. The field drives the closed dipole
transition with arbitrary values of the angular momenta and of
the ground and excited state. The steady-state density matrix is expressed in
terms of spherical harmonics of a complex direction given by the field
polarization vector. The generalization to the case of broad-band radiation is
given. We indicate various applications of these results.Comment: revtex, 26 pages, including 3 eps figures; PRA accepted for
publication;v2 three typos are fixe
Pure superposition states of atoms generated by a bichromatic elliptically polarized filed
We find specific polarizations of components of a bichromatic field, which
allow one to prepare pure superposition states of atoms, using the coherent
population trapping effect. These states are prepared in the system
of Zeeman substates of the ground-state hyperfine levels with arbitrary angular
momenta and . It is established that, in general case , the
use of waves with elliptical polarizations (
field configuration for alkali metal atoms) is necessary for the pure state
preparation. We analytically show an unique advantage of the D1 line of alkali
metal atoms, which consists in the possibility to generate pure
states even in the absence of spectral resolution of the excited-state
hyperfine levels, contrary to the D2 line.Comment: revtex4, 6 pages including 2 eps figure
On the unique possibility to increase significantly the contrast of dark resonances on D1 line of Rb
We propose and study, theoretically and experimentally, a new scheme of
excitation of a coherent population trapping resonance for D1 line of alakli
atoms with nuclear spin by bichromatic linearly polarized light ({\em
lin}{\em lin} field) at the conditions of spectral resolution of the
excited state. The unique properties of this scheme result in a high contrast
of dark resonance for D1 line of Rb.Comment: 9 pages, 7 figures. This material has been partially presented on
ICONO-2005, 14 May 2005, St. Petersburg, Russia. v2 references added; text is
changed a bi
Quantum coherence in a degenerate two-level atomic ensemble: for a transition
For a transition driven by a linearly polarized
light and probed by a circularly light, quantum coherence effects are
investigated. Due to the coherence between the drive Rabi frequency and Zeeman
splitting, electromagnetically induced transparency, electromagnetically
induced absorption, and the transition from positive to negative dispersion are
obtained, as well as the populations coherently oscillating in a wide spectral
region. At the zero pump-probe detuning, the subluminal and superluminal light
propagation is predicted. Finally, coherent population trapping states are not
highly sensitive to the refraction and absorption in such ensemble.Comment: 9 pages, 6 figure
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