Observation of the $4f^{14}6s^{2}~^1S_0- 4f^{13}5d6s^{2}(J=2)$ clock transition at 431 nm in $^{171}$Yb

Abstract

We report on the observation of the $4f^{14}6s^{2}~^1S_0- 4f^{13}5d6s^{2}(J=2)$ transition at 431 nm in $^{171}$Yb by depleting atoms in a magneto-optical trap formed by the $6s^{2}~^1S_0-6s6p~^3P_1$ intercombination transition. The absolute frequency of the transition to the $F=3/2$ state is determined to be $695~171~054~858.1(8.2)$~kHz against physical realization of Coordinated Universal Time maintained by the National Metrology Institute of Japan with a frequency comb. The $g$ factor of the transition to the $F=3/2$ state and the A hyperfine constant are measured to be $g_J=1.54(13)$ and 1123.354(13)~MHz, respectively. More precise spectroscopy of this transition can lead to searches for time variation of the fine structure constant and searches for new physics with isotope shift measurements.