144 research outputs found
Observation of Three-dimensional Long-range Order in Smaller Ion Coulomb Crystals in an rf Trap
Three-dimensional long-range ordered structures in smaller and
near-spherically symmetric Coulomb crystals of ^{40}Ca^+ ions confined in a
linear rf Paul trap have been observed when the number of ions exceeds ~1000
ions. This result is unexpected from ground state molecular dynamics (MD)
simulations, but found to be in agreement with MD simulations of metastable ion
configurations. Previously, three-dimensional long-range ordered structures
have only been reported in Penning traps in systems of ~50,000 ions or more.Comment: 5 pages; 4 figures; to appear in Phys. Rev. Lett.; changed content
Detection of Single Ion Spectra by Coulomb Crystal Heating
The coupled motion of ions in a radiofrequency trap has been used to connect
the frequency- dependent laser-induced heating of a sympathetically cooled
spectroscopy ion with changes in the fluorescence of a laser-cooled control
ion. This technique, sympathetic heating spectroscopy, is demonstrated using
two isotopes of calcium. In the experiment, a few scattered photons from the
spectroscopy ion are transformed into a large deviation from the steady-state
fluorescence of the control ion. This allows us to detect an optical transition
where the number of scattered photons is below our fluorescence detection
limit. Possible applications of the technique to molecular ion spectroscopy are
briefly discussed.Comment: 7 Pages,10 Figure
Sensing RF fields with a distant stand-alone Rydberg-atomic receiver
We combine a rubidium vapour cell with a corner-cube prism reflector to form
a passive RF receiver, allowing the detection of microwave signals at a
location distant from the active components required for atomic sensing. This
compact receiver has no electrical components and is optically linked to the
active base station by a pair of free-space laser beams that establish an
electromagnetically induced transparency scenario in the atomic vapour.
Microwave signals at the receiver location are imprinted onto an optical signal
which is detected at the base station. Our stand-alone receiver architecture
adds important flexibility to Rydberg-atom based sensing technologies, which
are currently subject to significant attention. We demonstrate a ~20 m link
with no particular effort and foresee significant future prospects of achieving
a much larger separation between receiver and base station
An ion ring in a linear multipole trap for optical frequency metrology
A ring crystal of ions trapped in a linear multipole trap is studied as a
basis for an optical frequency standard. The equilibrium conditions and cooling
possibilities are discussed through an analytical model and molecular dynamics
simulations. A configuration which reduces the frequency sensitivity to the
fluctuations of the number of trapped ions is proposed. The systematic shifts
for the electric quadrupole transition of calcium ions are evaluated for this
ring configuration. This study shows that a ring of 10 or 20 ions allows to
reach a short term stability better than for a single ion without introducing
limiting long term fluctuations
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