Three-dimensional viscous confinement and cooling of atoms by resonance radiation pressure

Abstract

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 \ensuremath{\sim}${10}^{6}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ and a temperature of \ensuremath{\sim}240 \ensuremath{\mu}K corresponding to a rms velocity of \ensuremath{\sim}60 cm/sec. This temperature is approximately the quantum limit for this atomic transition. The decay time for half the atoms to escape a \ensuremath{\sim}0.2${\mathrm{cm}}^{3}$ confinement volume is \ensuremath{\sim}0.1 sec.