Power-dependent loss from an ytterbium magneto-optic trap

Radiative decay of excited P-1(1) states to metastables is expected to limit attainable lifetimes in magneto-optic traps (MOTs) containing alkaline-earth-metal-like atoms. We present measurements of power-dependent loss from a (6s(2))S-1(0)-(6s6p)P-1(1) ytterbium MOT, show that the observed power dependence is consistent with radiative decay from the (6s6p)P-1(1) excited state leading to population of lower-lying metastable states, and determine the (6s6p) P-1(1)-to-metastable state decay rate. With weak excitation of the (6s(2))S-1(0)-(6s6p)P-1(1) trapping transition, MOT lifetimes approaching 800 ms are observed.