Radiative properties of rubidium atoms trapped in solid neon and parahydrogen

It is known from ensemble measurements that rubidium atoms trapped in solid parahydrogen have favorable properties for quantum sensing of magnetic fields. To use a single atom as sensor requires technique capable efficiently measuring the internal state atom, such laser-induced fluorescence. In this work we search fluorescence ensembles and, separately, neon. find no evidence over range explored, and place upper limits on radiative branching ratio. neon, observe laser induced fluorescence, measure spectrum emitted light, excited lifetime matrix. Bleaching excitation light also reported.