Measurement of hyperfine structure and isotope shifts in the Dy 421 nm transition

A measurement of the hyperfine coefficients and isotope shifts for the atomic dysprosium 421.291 nm transition (4f(10)6s(2),J=8-->4f(10)6s6p,J=9) using atomic beam laser-induced fluorescence spectroscopy is presented. A King plot analysis is performed to determine a specific mass shift of deltanu(sms)(164-162)=11(7) MHz for the 421 nm transition, confirming the pure 4f(10)6s6p configuration of the excited state. This transition is currently being explored for laser cooling of an atomic beam of dysprosium used in a search for a temporal variation of the fine-structure constant.