297 research outputs found
Atom trapping and guiding with a subwavelength-diameter optical fiber
We suggest using an evanescent wave around a thin fiber to trap atoms. We
show that the gradient force of a red-detuned evanescent-wave field in the
fundamental mode of a silica fiber can balance the centrifugal force when the
fiber diameter is about two times smaller than the wavelength of the light and
the component of the angular momentum of the atoms along the fiber axis is in
an appropriate range. As an example, the system should be realizable for Cesium
atoms at a temperature of less than 0.29 mK using a silica fiber with a radius
of 0.2 m and a 1.3-m-wavelength light with a power of about 27 mW.Comment: 5 pages, 5 figure
Focusing of atoms with strongly confined light potentials
Focusing of atoms with light potentials is studied. In particular, we
consider strongly confined, cylindrical symmetric potential, and demonstrate
their applications in both red and blue-detuned focusing of atoms. We also
study the influence of aberrations, and find that a resolution of 1 nm should
in principle be possible.Comment: 23 pages, 9 figures, Submitted to Optics Communication
Atomic matter wave scanner
We report on the experimental realization of an atom optical device, that
allows scanning of an atomic beam. We used a time-modulated evanescent wave
field above a glass surface to diffract a continuous beam of metastable Neon
atoms at grazing incidence. The diffraction angles and efficiencies were
controlled by the frequency and form of modulation, respectively. With an
optimized shape, obtained from a numerical simulation, we were able to transfer
more than 50% of the atoms into the first order beam, which we were able to
move over a range of 8 mrad.Comment: 4 pages, 4 figure
Guiding of cold atoms by a red-detuned laser beam of moderate power
We report measurements on the guiding of cold Rb atoms from a
magneto-optical trap by a continuous light beam over a vertical distance of 6.5
mm. For moderate laser power (85 mW) we are able to capture around 40% of
the cold atoms. Although the guide is red-detuned, the optical scattering rate
at this detuning (70 GHz) is acceptably low. For lower detuning (30
GHz) a larger fraction was guided but radiation pressure starts to push the
atoms upward, effectively lowering the acceleration due to gravity. The
measured guided fraction agrees well with an analytical model.Comment: final version, 6 pages, incl. 6 figure
How to measure the wave-function absolute squared of a moving particle by using mirrors
We consider a slow particle with wave function , moving
freely in some direction. A mirror is briefly switched on around a time and
its position is scanned. It is shown that the measured reflection probability
then allows the determination of . Experimentally
available atomic mirrors should make this method applicable to the
center-of-mass wave function of atoms with velocities in the cm/s range.Comment: 4 pages, 5 figure
Magneto-Optical Trap for Thulium Atoms
Thulium atoms are trapped in a magneto-optical trap using a strong transition
at 410 nm with a small branching ratio. We trap up to atoms at
a temperature of 0.8(2) mK after deceleration in a 40 cm long Zeeman slower.
Optical leaks from the cooling cycle influence the lifetime of atoms in the MOT
which varies between 0.3 -1.5 s in our experiments. The lower limit for the
leaking rate from the upper cooling level is measured to be 22(6) s. The
repumping laser transferring the atomic population out of the F=3 hyperfine
ground-state sublevel gives a 30% increase for the lifetime and the number of
atoms in the trap.Comment: 4 pages, 6 figure
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