Spectroscopy of the ²S_1/2 → ²P_3/2 transition in Yb II: Isotope shifts, hyperfine splitting, and branching ratios

We report on spectroscopic results on the ²S_1/2 → ²P_3/2 transition in single trapped Yb⁺ ions. We measure the isotope shifts for all stable Yb⁺ isotopes except ¹⁷³Yb⁺, as well as the hyperfine splitting of the  ²P_3/2 state in ¹⁷¹Yb⁺. Our results are in agreement with previous measurements but are a factor of 5-9 more precise. For the hyperfine constant A(²P_3/2) = 875.4(10) MHz our results also agree with previous measurements but deviate significantly from theoretical predictions. We present experimental results on the branching ratios for the decay of the ²P_3/2 state. We find branching fractions for the decay to the ²D_3/2 state and ²D_5/2 state of 0.17(1)% and 1.08(5)%, respectively, in rough agreement with theoretical predictions. Furthermore, we measured the isotope shifts of the ²F_7/2 → ¹D[5/2]_5/2 transition and determine the hyperfine structure constant for the ¹D[5/2]_5/2 state in ¹⁷¹Yb⁺ to be A(¹D[5/2]_5/2)= -107 (6) MHz.