Spectroscopy of a narrow-line optical pumping transition in dysprosium

Abstract

We present measurements of the hyperfine coefficients and isotope shifts of the Dy I $683.731$nm transition, using saturated absorption spectroscopy on an atomic beam. A King Plot is drawn resulting in an updated value for the specific mass shift $\hat{I}´\hat{I}{½}_{684,\mathrm{sms}}^{164-162}=-534\pm 17MHz$. Using fluorescence spectroscopy we measure the excited state lifetime $\ddot{I}{„}_{684}=1.68(5)\hat{I}¼$s, yielding a linewidth of ${\hat{I}}_{684}^3=95\pm 3kHz$. We give an upper limit to the branching ratio between the two decay channels from the excited state showing that this transition is useable for optical pumping into a dark state and demagnetization cooling.