269 research outputs found
Single-atom trapping and transport in DMD-controlled optical tweezers
We demonstrate the trapping and manipulation of single neutral atoms in
reconfigurable arrays of optical tweezers. Our approach offers unparalleled
speed by using a Texas Instruments Digital Micro-mirror Device (DMD) as a
holographic amplitude modulator with a frame rate of 20,000 per second. We show
the trapping of static arrays of up to 20 atoms, as well as transport of
individually selected atoms over a distance of 25{\mu}m with laser cooling and
4{\mu}m without. We discuss the limitations of the technique and the scope for
technical improvements
Reply to the Comment on `Deterministic Single-Photon Source for Distributed Quantum Networking'
Reply to the comment of H. J. Kimble [quant-ph/0210032] on the experiment
realizing a "deterministic single-photon source for distributed quantum
networking" by Kuhn, Hennrich, and Rempe [Phys. Rev. Lett. 89, 067901 (2002),
quant-ph/0204147].Comment: 1 page 1 figur
Three Dimensional Raman Cooling using Velocity Selective Rapid Adiabatic Passage
We present a new and efficient implementation of Raman cooling of trapped
atoms. It uses Raman pulses with an appropriate frequency chirp to realize a
velocity selective excitation through a rapid adiabatic passage. This method
allows to address in a single pulse a large number of non zero atomic velocity
classes and it produces a nearly unity transfer efficiency. We demonstrate this
cooling method using cesium atoms in a far-detuned crossed dipole trap.
Three-dimensional cooling of atoms down to K is
performed in 100 ms. In this preliminary experiment the final atomic density is
at/cm (within a factor of 2) and the phase-space
density increase over the uncooled sample is 20. Numerical simulations indicate
that temperatures below the single photon recoil temperature should be
achievable with this method.Comment: OSA TOPS on Ultracold Atoms and BEC 7 (1997) 5
Transition from antibunching to bunching in cavity QED
The photon statistics of the light emitted from an atomic ensemble into a
single field mode of an optical cavity is investigated as a function of the
number of atoms. The light is produced in a Raman transition driven by a pump
laser and the cavity vacuum [M.Hennrich et al., Phys. Rev. Lett. 85, 4672
(2000)], and a recycling laser is employed to repeat this process continuously.
For weak driving, a smooth transition from antibunching to bunching is found
for about one intra-cavity atom. Remarkably, the bunching peak develops within
the antibunching dip. For saturated driving and a growing number of atoms, the
bunching amplitude decreases and the bunching duration increases, indicating
the onset of Raman lasing.Comment: 4 pages, 4 figure
Nonlinear Zeeman Effects in the Cavity-Enhanced Emission of Polarised Photons
We theoretically and experimentally investigate nonlinear Zeeman effects
within a polarised single-photon source that uses a single 87Rb atom strongly
coupled to a high finesse optical cavity. The breakdown of the atomic hyperfine
structure in the D2 transition manifold for intermediate strength magnetic
fields is shown to result in asymmetric and, ultimately, inhibited operation of
the polarised atom-photon interface. The coherence of the system is considered
using Hong-Ou-Mandel interference of the emitted photons. This informs the next
steps to be taken and the modelling of future implementations, based on
feasible cavity designs operated in regimes minimising nonlinear Zeeman
effects, is presented and shown to provide improved performance.Comment: 12 pages, 8 figure
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