Simultaneous two-photon resonant optical laser locking (STROLLing) in the hyperfine Paschen-Back regime

We demonstrate a technique to lock simultaneously two laser frequencies to each step of a two-photon transition in the presence of a magnetic field sufficiently large to gain access to the hyperfine Paschen–Back regime. A ladder configuration with the 5S1/2, 5P3/2, and 5D5/2 terms in a thermal vapor of Rb87 atoms is used. The two lasers remain locked for more than 24 h. For the sum of the laser frequencies, which represents the stability of the two-photon lock, we measure a frequency instability of less than the Rb D2 natural linewidth of 6 MHz for nearly all measured timescales

Quantitative optical spectroscopy of 87^{87}Rb vapour in the Voigt geometry in DC magnetic fields up to 0.4T

We present a detailed spectroscopic investigation of a thermal ⁸⁷Rb atomic vapour in magnetic fields up to 0.4T in the Voigt geometry. We fit experimental spectra with our theoretical model ElecSus and find excellent quantitative agreement, with RMS errors of backsim0.3%. We extract the magnetic field strength and the angle between the polarisation of the light and the magnetic field from the atomic signal and find excellent agreement to within backsim1% with a commercial Hall probe. Finally, we present an investigation of the relative sensitivity of this technique to variations in the field strength and angle with a view to enabling atom-based high-field vector magnetometry

Absorption spectroscopy and Stokes polarimetry in a 87Rb vapour in the Voigt geometry with a 1.5 T external magnetic field

This paper provides details of a spectroscopic investigation of a thermal 87Rb atomic vapour. The experiment was conducted with an external magnetic field of 1.5 T in the Voigt geometry. Very good quantitative agreement between experimental data and theory is found for all four Stokes parameters—with RMS errors of ~1.5% in all cases. From the fits to our experimental data a value for the magnetic field strength is extracted, along with the angle between the magnetic field and the polarisation of the light. The effects of the cell window birefringence on the optical rotation signals are characterised. This allows us to carry out precise measurements at a high field strength and arbitrary geometries, allowing further development of possible areas of application for atomic magnetometers