Transition Frequencies And Hyperfine Structure In In-113,115(+): Application Of A Liquid-Metal Ion Source For Collinear Laser Spectroscopy

We demonstrate an application of a liquid-metal ion source for collinear laser spectroscopy in proof-of -principle measurements on naturally abundant In+. The superior beam quality, i.e., the actively stabilized current and energy of a beam with very low transverse emittance, allowed us to perform precision spectroscopy on the 5s(2) S-1(0) -> 5s5p P-3(1) intercombination transition in In-115(+), which is, to our knowledge, the slowest transition measured with collinear fluorescence laser spectroscopy so far. By applying collinear and anticollinear spectroscopy, we improved the center-of-gravity frequency nu(cg) = 1 299 617 759.3 (1.2) MHz and the hyperfine constants A = 6957.19 (28) MHz and B = -443.7 (2.4) MHz by more than one order of magnitude. A similar accuracy was reached for (11)3(I)n(+) in combination with the literature data, and the isotope shift between both naturally abundant isotopes was deduced to nu(In-113) - nu(In-115) = 696.3 (3.1) MHz. Nuclear alignment induced by optical pumping in a preparation section of the ion beam line was demonstrated as a pump-and-probe approach to provide sharp features on top of the Doppler-broadened resonance profile.