Ultracold metastable helium: Ramsey fringes and atom interferometry

W. Vassen*, R. P.M.J.W. Notermans, R. J. Rengelink, R. F.H.J. van der Beek

*Corresponding author for this work

Research output: Chapter in Book / Report / Conference proceedingChapterAcademicpeer-review


We report on interference studies in the internal and external degrees of freedom of metastable triplet helium atoms trapped near quantum degeneracy in a 1:5 μm optical dipole trap. Applying a single π/2 rf pulse we demonstrate that 50% of the atoms initially in the m = +1 state can be transferred to the magnetic field insensitive m = 0 state. Two π/2 pulses with varying time delay allow a Ramseytype measurement of the Zeeman shift for a high precision measurement of the 2 3S1-2 1S0 transition frequency. We show that this method also allows strong suppression of mean-field effects on the measurement of the Zeeman shift, which is necessary to reach the accuracy goal of 0.1 kHz on the absolute transition frequencies. Theoretically the feasibility of using metastable triplet helium atoms in the m = 0 state for atom interferometry is studied demonstrating favorable conditions, compared to the alkali atoms that are used traditionally, for a non-QED determination of the fine structure constant.

Original languageEnglish
Title of host publicationExploring the World with the Laser
Subtitle of host publicationDedicated to Theodor Hänsch on his 75th Birthday
Place of PublicationCham
PublisherSpringer International Publishing Switzerland
Number of pages20
ISBN (Electronic)9783319643465
ISBN (Print)9783319643458
Publication statusPublished - 3 Jan 2018


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