Population trapping in excited Yb ions

Abstract

Resonant laser excitation of Yb ions confined in an rf ion trap is found to result in perfect population trapping in the highly metastable $^{2}\mathrm{F}_{7/2}$ state. The lifetime of this level is measured to be greater than 8 days. Population and depopulation of this level under narrow- and broad-band laser excitation conditions is investigated and its potentiality for ultimate-resolution laser spectroscopy indicated.