Precision spectroscopy of Helium
Authors: Cancio P., Giusfredi G., de Mauro C., Krachmalnicoff V., Mazzotti D., De Natale P., Inguscio M.
Autors Affiliation: Istituto Nazionale di Ottica Applicata – CNR
European Laboratory for Non-linear Spectroscopy (LENS)
Dipartimento di Fisica, Università di Firenze
Dipartimento di Fisica, Università di Siena
Abstract: Accurate Quantum-Electrodynamics (QED) tests of the simplest bound three body atomic system are performed by precise laser spectroscopic measurements in atomic Helium. In this paper, we present a review of measurements between triplet states at 1083 nm (23S-23P) and at 389 nm (2 3S-33P). In 4He, such data have been used to measure the fine structure of the triplet P levels and, then, to determine the fine structure constant when compared with equally accurate theoretical calculations. Moreover, the absolute frequencies of the optical transitions have been used for Lamb-shift determinations of the levels involved with unprecedented accuracy. Finally, determination of the He isotopes nuclear structure and, in particular, a measurement of the nuclear charge radius, are performed by using hyperfine structure and isotope-shift measurements. © 2005 American Institute of Physics.
KeyWords: helium spectroscopy