Investigations of Atomic Transitions of the D2 Line of Potassium in Strong Magnetic Fields Using Saturated Absorption Technique in a Microcell

Atomic transitions of ³⁹K, D₂ line are studied in strong longitudinal magnetic fields, up to 1000 G, with a high spectral resolution. The saturated absorption (SA) method was used in a micro-cell filled with K vapors with a thickness of L= 30 µm. A double differentiation of the SA spectrum was carried out, which made it possible to obtain narrow (~50 MHz) atomic lines and study individual transition frequency and probabilistic behavior. Among alkali metals, the K atoms have the smallest hyperfine splitting of the ground levels. This allows one to observe the break of the coupling between the electronic total angular momentum J and nuclear I angular momentums at relatively low magnetic fields B > 300 G. In the case of using circularly polarized radiation (σ⁺ or σ^–), two groups (each consisting of four) equidistantly located total eight atomic transitions are recorded in strong magnetic fields. The experimental results are well described by a known theoretical model.