Loading and compressing Cs atoms in a very far-off-resonant light trap

Abstract

We describe an experiment in which $3\times {10}^7\hspace{0.5em}\mathrm{Cs}$ atoms are loaded into a $400\hspace{0.5em}\mu \mathrm{m}$ crossed beam far-off-resonant trap (FORT) that is only $2\hspace{0.5em}\mu \mathrm{K}$ deep. A high-density sample is prepared in a magneto-optic trap, cooled in a three-dimensional far-off-resonant lattice (FORL), optically pumped into the lowest-energy state, adiabatically released from the FORL, magnetically levitated, and transferred to the final trap with a phase-space density of ${10}^{-3}.$ Spontaneous emission in the FORT is negligible, and we have compressed the atoms in the FORT to a spatial density of $2\times {10}^{13}\hspace{0.5em}{\mathrm{a}\mathrm{t}\mathrm{o}\mathrm{m}\mathrm{s}/\mathrm{c}\mathrm{m}}^3.$ Evaporative cooling under these conditions proceeds rapidly.