Frequency metrology on the 4s(2)S(1/2)-4p(2)P(1/2) transition in Ca-40(+) for a comparison with quasar data
Berg, S.A. van den
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High accuracy frequency metrology on the 4s S-2(1/2)-4p P-2(1/2) transition in calcium ions is performed using laser cooled and crystallized ions in a linear Paul trap. Calibration is performed with a frequency comb laser, resulting in a transition frequency of f = 755 222 766.2 (1.7) MHz. The accuracy presents an improvement of more than one order of magnitude, and will facilitate a comparison with quasar data in a search for a possible change of the fine structure constant on a cosmological time scale.