Optical repumping of triplet $P$-states enhances magneto-optical   trapping of ytterbium atoms
  Radiative decay from the excited $^1P_1$ state to metastable $^3P_2$ and $^3P_0$ states is expected to limit attainable trapped atomic population in a magneto-optic trap of ytterbium (Yb) atoms. In experiments we have carried out with optical repumping of $^3P_{0,2}$ states to $^3P_1$, we observe enhancement of trapped atoms yield in the excited $^1P_1$ state. The individual decay rate to each metastable state is measured and the results show an excellent agreement with the theoretical values. 
Jun Woo Cho, Han-gyeol Lee, Sangkyung Lee, Jaewook Ahn, Won-Kyu Lee,   Dai-Hyuk Yu, Sun Kyung Lee, and Chang Yong Park
physics.atom-ph