We report the viscous confinement and cooling of neutral sodium atoms in three dimensions via the radiation pressure of counterpropagating laser beams. These atoms have a density of about ∼${10}^6$ ${\mathrm{cm}}^{\mathrm{-}3}$ and a temperature of ∼240 μK corresponding to a rms velocity of ∼60 cm/sec. This temperature is approximately the quantum limit for this atomic transition. The decay time for half the atoms to escape a ∼0.2${\mathrm{cm}}^3$ confinement volume is ∼0.1 sec.

• Received 25 April 1985

DOI:https://doi.org/10.1103/PhysRevLett.55.48

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