217 research outputs found
Absolute Single Ion Thermometry
We describe and experimentally implement a single-ion local thermometry
technique with absolute sensitivity adaptable to all laser-cooled atomic ion
species. The technique is based on the velocity-dependent spectral shape of a
quasi-dark resonance tailored in a J J transition such that the
two driving fields can be derived from the same laser source leading to a
negligible relative phase shift. We validated the method and tested its
performances in an experiment on a single 88 Sr + ion cooled in a surface
radio-frequency trap. We first applied the technique to characterise the
heating-rate of the surface trap. We then measured the stationary temperature
of the ion as a function of cooling laser detuning in the Doppler regime. The
results agree with theoretical calculations, with an absolute error smaller
than 100 K at 500 K, in a temperature range between 0.5 and 3 mK and
in the absence of adjustable parameters. This simple-to-implement and reliable
method opens the way to fast absolute measurements of single-ion temperatures
in future experiments dealing with heat transport in ion chains or
thermodynamics at the single-ion level
Strong quantum correlations in four wave mixing in Rb vapor
We study quantum intensity correlations produced using four-wave mixing in a
room-temperature rubidium vapor cell. An extensive study of the effect of the
various parameters allows us to observe very large amounts of non classical
correlations.Comment: 8 pages and 8 figures; work presented at the SPIE Photonics Europe
conference (Brussels, 2010
Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal
We measured by laser spectroscopy the isotope shifts between
naturally-occurring even-isotopes of strontium ions for both the
5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2} (violet) and the 4d\,\,^2D_{3/2}\to
5p\,\,^2P_{1/2} (infrared) dipole-allowed optical transitions. Fluorescence
spectra were taken by simultaneous measurements on a two-component Coulomb
crystal in a linear Paul trap containing -- laser-cooled Sr
ions. The isotope shifts are extracted from the experimental spectra by fitting
the data with the analytical solution of the optical Bloch equations describing
a three-level atom in interaction with two laser beams. This technique allowed
us to increase the precision with respect to previously reported data obtained
by optogalvanic spectroscopy or fast atomic-beam techniques. The results for
the 5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2} transition are
MHz and MHz, in
agreement with previously reported measurements. In the case of the previously
unexplored 4d\,\,^2D_{3/2}\to 5p\,\,^2P_{1/2} transition we find
MHz and MHz. These
results provide more data for stringent tests of theoretical calculations of
the isotope shifts of alkali-metal-like atoms. Moreover, they simplify the
identification and the addressing of Sr isotopes for ion frequency
standards or quantum-information-processing applications in the case of
multi-isotope ion strings.Comment: 19 pages; 5 figures; accepted on Phys. Rev. A (http://pra.aps.org/
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