Observation by two-photon laser spectroscopy of the4d105sS1∕22→4d95s2D5∕22clock transition in atomic silver

Abstract

We report the observation of the very narrow $4{d}^{10}5s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{\rightarrow}4{d}^{9}5{s}^{2}\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ transition in atomic silver. The frequencies of the hyperfine components in $^{107}\mathrm{Ag}$ and $^{109}\mathrm{Ag}$ have been measured using Doppler-free two-photon laser spectroscopy of a thermal beam and heterodyne calibration with respect to the ${a}_{1}$ component of the $62P(4\text{\ensuremath{-}}5)$ line in molecular iodine near $661\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. For the center of gravity of a mixture of natural abundance, we deduce the value $906\phantom{\rule{0.2em}{0ex}}641\phantom{\rule{0.2em}{0ex}}295.77(19)\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$. For the isotope shift, we obtain $\ensuremath{\nu}(^{109}\mathrm{Ag})\ensuremath{-}\ensuremath{\nu}(^{107}\mathrm{Ag})=564.15(37)\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, from which we deduce the frequency and isotope shift of the $4{d}^{10}5s\phantom{\rule{0.2em}{0ex}}^{2}S_{1∕2}\ensuremath{\rightarrow}4{d}^{10}6p\phantom{\rule{0.2em}{0ex}}^{2}P_{3∕2}$ transition at $206\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$.