We report on the observation of the 4f146s2 1S0​−4f135d6s2(J=2) transition at 431 nm in 171Yb by depleting atoms in
a magneto-optical trap formed by the 6s2 1S0​−6s6p 3P1​ intercombination
transition. The absolute frequency of the transition to the F=3/2 state is
determined to be 695Â 171Â 054Â 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 gJ​=1.54(13) and
1123.273(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.Comment: 5 pages, 4 figure