High Precision Measurements on Helium at 1083 nm
We present a review of the helium spectroscopy, related to transitions between 23 S and 23 P states around 1083 nm. A detailed description of our measurements, that have produced the most accurate value of the 23 P 0–23 P 1 fine structure interval, is given. It could produce an accurate determination (34 ppb) of the fine structure constant α. Improvements in the experimental set up are presented. In particular, a new frequency reference of the laser system has been developed by frequency lock of a 1083 nm diode laser to iodine hyperfine transitions around its double of frequency. The laser frequency stability, at 1 s timescale, has been improved of, at least, two orders of magnitude, and even better for longer time scales. Simultaneous 3 He—4 He spectroscopy, as well as absolute frequency measurements of 1083 nm helium transitions can be allowed by using the I2-locked laser as frequency standard. We discuss the implication of these measurements for a new determination of the isotope and 23S Lamb shifts.
KeywordsFrequency Stability Optical Feedback Helium Transition Slave Laser Master Laser
Unable to display preview. Download preview PDF.
- 2.V.W. Hughes: Comm. At. Mol. Phys. 1, 5 (1969)Google Scholar
- 4.F Minardi et al.: Phys. Rev. Lett. 82, 1112 (1999) P. Cancio et al.: ‘Precision spectroscopy of Helium’. In: Atomic Physics 16, International conference, Windsor-Canada, August 1998, ed. by W.E. Baylis, G.W.F. Drake (AIP, Woodbury, New York 1999) pp.42-57Google Scholar
- 5.P. Cancio et al.: ‘Fine structure constant α and precision laser spectroscopy of Helium’. In: Recent advances in Metrology and Fundamental constants, Proceedings of the International School of Physics “Enrico Fermi”, ed. By S. Leschiutta, T.J. Quinn (SIF, Bologna) in press Google Scholar
- 11.J. Wen. Ph.D. Thesis, Harvard University (1996)Google Scholar
- 12.W. Frieze et al: presented at The Hydrogen atom II meeting (unpublished)Google Scholar
- 13.G. Gabrielse: Private communication Google Scholar
- 19.K. Pachucki, presented at the conference Hydrogen Atom, 2 (unpublished); K. Pachucki, J. Sapirstein: Private communication Google Scholar
- 22.N. Picque et al.: J. Opt. Soc. Ame. B, (2000) submitted Google Scholar
- 23.G.W.F. Drake: this edition, pp. 57–78Google Scholar