Accumulation of Cold Cesium Molecules via Photoassociation in a Mixed Atomic and Molecular Trap

We have realized a mixed atomic and molecular trap, constituted by a Cs vapor-cell magneto-optical trap and a quadrupolar magnetic ${\mathrm{C}\mathrm{s}}_2$ trap, using the same magnetic field gradient. We observed the trapping of $2\times {10}^5$ molecules, formed and accumulated in the metastable $a{}^3\Sigma _u^{+}$ state at a temperature of $30\pm 10\mu \mathrm{K}$ through a $\simeq 150\mathrm{m}\mathrm{s}$ photoassociation process. The lifetime of the trapped molecular cloud limited by the Cs background gas pressure is on the order of 1 s.