Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

First pure frequency measurement of an optical transition in helium: Lamb shift on the 2[sup 3][ital S][sub 1] metastable level

Journal Article · · Physical Review Letters; (United States)
; ; ;  [1];  [2]
  1. Department of Physics and European Laboratory for Nonlinear Spectroscopy (LENS), University of Florence, Largo E. Fermi, 2 I-50125 Firenze (Italy)
  2. Laboratorie Kastler-Brossel'' de l' Ecole Normale Superieure, Universite Pierre et Marie Curie, Paris (France)
The 2[sup 3][ital S][sub 1-]3[sup 3][ital P][sub 0][sup 4]He transition at [lambda][sub 0]=389 nm is measured with respect to a previously frequency calibrated [sup 87]Rb two-photon transition at 2[lambda][sub 0]=778 nm. The [sup 4]He absolute frequency is 770 732 839 058 (190) kHz, with an accuracy of 2.4 parts in 10[sup 10]. A Lamb shift value of +4057.61 (79) MHz, with 600 kHz uncertainty arising from the theoretical position of the 3[sup 3][ital P][sub 0] energy level, is extracted for the 2[sup 3][ital S][sub 1] level. This value is more than 2 orders of magnitude more accurate than the current best theoretical predictions.
OSTI ID:
7272220
Journal Information:
Physical Review Letters; (United States), Journal Name: Physical Review Letters; (United States) Vol. 73:1; ISSN 0031-9007; ISSN PRLTAO
Country of Publication:
United States
Language:
English