Repumping and spectroscopy of laser-cooled Sr atoms using the (5s5p)3P2-(5s4d)3D2 transition

We describe repumping and spectroscopy of laser-cooled strontium (Sr) atoms using the (5s5p)P-3(2)-(5s4d)D-3(2) transition. Atom number in a magneto-optical trap is enhanced by driving this transition because Sr atoms that have decayed into the (5s5p)P-3(2) dark state are repumped back into the (5s2)S-1(0) ground state. Spectroscopy of Sr-84, Sr-86, Sr-87 and Sr-88 improves the value of the (5s5p)P-3(2)-(5s4d)D-3(2) transition frequency and determines the isotope shifts for the transition accurately enough to guide laser-cooling experiments with less abundant isotopes.