Precision spectroscopy of Helium atom

Year: 2005

Authors: Cancio P., Giusfredi G., Mazzotti D., De Natale P., Krachmalnicoff V., Inguscio M.

Autors Affiliation: Istituto Nazionale di Ottica Applicata (INOA-CNR), European Laboratory for Non-Linear Spectroscopy (LENS), Italy; LENS, Dipartimento di Fisica, Università Firenze, Via N. Carrara 1, I-50019 Sesto Fiorentino, Italy

Abstract: Quantum electrodynamic theory (QED) of the simplest bound-three-body system is now stringently tested by precise spectroscopic frequency measurements in Helium. Alternatively, comparison between He measurements and theory could be used for accurate determination of some fundamental quantities, as for example, the fine structure constant a, and the differences of nuclear charge radii between two 3He and 4He. In the following, we review our precise spectroscopic measurements on the 1083 nm Helium transition, connecting the triplet 2S and 2P states. Frequency differences among the 1083 nm measured frequencies give precise values of the fine structure (FS) and hyperfine structure (HFS) splittings of the 23P level in 4He and 3He respectively, and of the isotope shift (IS) between these two isotopes. Implications of these results in the a determination as well as for nuclear charge radii and structure are discussed.

Conference title: The 17th International Conference in Laser Spectroscopy (ICOLS 2005)

More Information: Sponsors: Agilent Technologies; Coherent (UK) Ltd; Coherent Inc.; Elliot Scientific; Engineering and Physical Sciences Research Council (EPSRC); et al.
KeyWords: Atomic physics; Isotopes; Laser spectroscopy; Quantum electronics, Fine structure constants; Frequency differences; Frequency measurements; Helium transition; Hyperfine structure; Precision spectroscopy; Quantum electrodynamics; Spectroscopic measurements, Helium