Cooling of Cesium Atoms in Gray Optical Molasses down to 1.1
D. Boiron, A.
Michaud, P. Lemonde, Y. Castin, C. Salomon
Kastler-Brossel and Collège de France, 24 rue Lhomond, Paris
S. Weyers, K. Szymaniec, L. Cognet, A. Clairon
LPTF-BNM, Observatoire de Paris, 61 avenue de l'Observatoire, Paris
in: Proceedings EQEC. 8-13 sept 1996, p. 173 (1996) (reference)
in Grey Molasses (GM)1,2
occurs when the laser
frequency is tuned to the blue side of a J --> J or J --> J-1
transition (\omega l - \omega at
> 0). Some states are then not coupled to the
laser light. A Sysiphus effect between coupled states \Psi C,
spatially modulated light-shifts and uncoupled states \Psi NC
which experience no light-shift, accumulates the atoms into \Psi NC
with very low momenta, on the order of the photon recoil
Experiments are performed on the F=3 --> F=2
transition of the cesium D2 line. We
show that GM have a lower ultimate temperature than that of J --> J+1 molasses.
With a time-of-flight technique, we find a minimum temperature of
1.1±0.1 µK at low atomic density (vRMS
= 8.3 mm/s = 2.4 vrecoil).
We measure the lifetime of GM as a function of laser parameters and
find cooling times on the order of 1 m/s. Finally, in spite of the
accumulation of atoms into uncoupled states, we find a linear
dependence of the temperature on the atomic density with a slope of 0.6
We interpret this effect as being due to photon reabsorption within the
cloud of cold atoms.
Temperature of grey molasses as a function of atomic peak density.
J.-Y. Courtois, Europhys.
p. 41 (1994).
Weidemüller, T. Esslinger, M.A. Ol'Shanii, A.
Hemmerich, T.W. Hänsch, Europhys. Lett. 27, p. 109 (1994).
- D. Boiron, C.
Triché, D.R. Meacher, P. Verkerk, G. Grynberg, Phys. Rev. A 52, p. R3425 (1995).
- D. Boiron, A.
Michaud, P. Lemonde, Y. Castin, C. salomon, S. Weyers, K. Szymaniec, A.
Clairon, "Laser Cooling of Cesium Atoms in Gray Optical
Molasses down to 1.1 µKelvin", Phys. Rev. A 53, p. R3734 (june