Inelastic Collisions in Optically Trapped Ultracold Metastable Ytterbium

Abstract

We report measurement of inelastic loss in dense and cold metastable ytterbium (Yb[${}^3{P}_2$]). Use of an optical far-off-resonance trap enables us to trap atoms in all magnetic sublevels, removing multichannel collisional trap loss from the system. Trapped samples of Yb[${}^3{P}_2$] are produced at a density of 2$\times 10^{13}$ cm${}^{-3}$ and temperature of 2 $\mu$K. We observe rapid two-body trap loss of Yb[${}^3{P}_2$] and measure the inelastic collision rate constant 1.0(3)$\times 10^{-11}$ cm${}^3$s${}^{-1}$. The existence of the fine-structure changing collisions between atoms in the ${}^3{P}_2$ state is strongly suggested.

4 pages, 4 figures