Saturated absorption technique used in potassium microcells for magnetic field sensing

• Published in: Laser physics Vol. 32; no. 10; pp. 105701 - 105705
• Main Authors: Sargsyan, Armen, Momier, Rodolphe, Leroy, Claude, Sarkisyan, David
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.10.2022; MAIK Nauka/Interperiodica
• Subjects: Atomic Physics; atomic spectroscopy; magnetometry; microcell; Physics
• ISSN: 1054-660X; 1555-6611
• DOI: 10.1088/1555-6611/ac8c42

Abstract It is demonstrated that the use of a micrometric thin 39 K vapor cell (MTC) and saturated absorption (SA) spectroscopy allows the formation of narrow atomic lines in the transmission spectrum without unwanted cross-over resonances. Another important feature is the small characteristic magnetic field value B 0 = A h f / μ B of 39 K, significantly smaller than for Rb and Cs. As a consequence, decoupling of J and I can be observed at relatively low magnetic fields ∼300 G, which results in the formation of two groups of four spectrally-resolved and equidistantly-positioned atomic transitions having the same amplitude (each group corresponds to a given circular polarization σ ± ) which we record using a simple experimental setup with a linearly polarized tunable diode-laser and a longitudinal magnetic field obtained with two permanent magnets. Fabrication of a MTC is much easier than the fabrication of the 39 K nanocells used in our previous works. A simple method to determine the magnitude of a wide range of B -fields with a spatial resolution of 30  µ m is presented, which is intrinsically calibrated and does not require a frequency reference.