35 research outputs found
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
Coherent population trapping resonances with linearly polarized light for all-optical miniature atomic clocks
We present a joint theoretical and experimental characterization of the
coherent population trapping (CPT) resonance excited on the D1 line of 87Rb
atoms by bichromatic linearly polarized laser light. We observe high-contrast
transmission resonances (up to 25%), which makes this excitation scheme
promising for miniature all-optical atomic clock applications. We also
demonstrate cancellation of the first-order light shift by proper choice of the
frequencies and relative intensities of the two laser field components. Our
theoretical predictions are in good agreement with the experimental results.Comment: 8 pages, 7 figure
A nonlinear frequency shift caused by asymmetry of the coherent population trapping resonance: a generalization
We investigate the coherent population trapping resonance induced by a
polychromatic optical field with an asymmetric spectrum, i.e., whose sidebands
equidistant from the carrier have unequal powers. A situation is considered
where a modulation is used to provide the so-called in-phase and quadrature
signals in the optical field's transmission, which are used for stabilization
of the local oscillator's frequency in chip-scale atomic clocks. In a general
case, the frequencies of the signals nonlinearly depend on the optical field's
intensity due to the asymmetry of the resonance. In this work, we demonstrate
a) that this effect stems from a multi-peak structure of the resonance; b) a
linear dependence of the frequency on the optical field's intensity at high
modulation values; c) that the regime of the resolved structure has more
advantages than suppression of the frequency shift due to the spectrum
asymmetry
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
Features of Magneto-Optical Resonances in an Elliptically Polarized Traveling Light Wave
The parameters of nonlinear absorption magneto-optical resonances in the
Hanle configuration have been studied as functions of the ellipticity of a
traveling light wave. It has been found that these parameters (amplitude,
width, and amplitude-to-width ratio) depend strongly on the polarization of the
light wave. In particular, the resonance amplitude can increase by more than an
order of magnitude when the polarization changes from linear to optimal
elliptic. It has been shown that this effect is associated with the Doppler
frequency shift for atoms in a gas. The theoretical results have been
corroborated in experiments in Rb vapor.Comment: 5 page