Optical spectroscopy of a microsized Rb vapour sample in magnetic fields up to 58 tesla

TL;DR

This study employs optical spectroscopy of a microsized rubidium vapor sample to measure magnetic fields up to 58 tesla with high precision, exploring atomic responses across different magnetic regimes.

Contribution

It introduces a novel high-field magnetometry technique using rubidium optical spectra, including the first measurement of the excited state Landé g-factor at these fields.

Findings

Achieved magnetic field measurement with 20 ppm uncertainty at high fields.

Derived the excited state Landé g-factor from spectral data.

Explored atomic transitions from hyperfine Paschen-Back to fine regimes.

Abstract

We use a magnetometer probe based on the Zeeman shift of the rubidium resonant optical transition to explore the atomic magnetic response for a wide range of field values. We record optical spectra for fields from few tesla up to 60 tesla, the limit of the coil producing the magnetic field. The atomic absorption is detected by the fluorescence emissions from a very small region with a submillimiter size. We investigate a wide range of magnetic interactions from the hyperfine Paschen-Back regime to the fine one, and the transitions between them. The magnetic field measurement is based on the rubidium absorption itself. The rubidium spectroscopic constants were previously measured with high precision, except the excited state Land\'e $g$-factor that we derive from the position of the absorption lines in the transition to the fine Paschen-Back regime. Our spectroscopic investigation, even if limited by the Doppler broadening of the absorption lines, measures the field with a 20 ppm uncertainty at the explored high magnetic fields. Its accuracy is limited to 75 ppm by the excited state Land\'e $g$-factor determination.