https://doi.org/10.1140/epjd/s10053-025-01112-9
Research - Atoms
Rb vapour Zeeman optical spectroscopy in a self-calibrated magnetic field
1
Laboratoire National des Champs Magnétiques Intenses, UPR 3228, CNRS-UT-UGA-INSA, F-31400, Toulouse Cedex, France
2
Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo B. Pontecorvo 3, I-56122, Pisa, Italy
3
Istituto Nazionale di Ottica-CNR, Via G. Moruzzi 1, I-56124, Pisa, Italy
a
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Received:
22
October
2025
Accepted:
18
December
2025
Published online:
12
January
2026
High-resolution optical spectroscopy of Rb atoms in an intermediate-Zeeman magnetic field regime is performed. Magnetic fields between 0.05 T and 0.13 T are measured. We introduce a measurement approach based on three-level 
systems where the open-loop frequency energy separation is determined by the applied magnetic field. Using this method an accuracy better than 100 ppm is reached in a measurement series. In parallel, on the basis of complementary measurements based on three-level V systems we obtain the first experimental value of the Landé g-factor of the first excited state for 
Rb, 
=0.66709(7), and for 
Rb, 
=0.6663(2). Our approach is unprecedented in the literature for Rb.
© The Author(s) 2025
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