Investigations of atomic transitions of 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 to study the frequency and probabilistic behavior of an individual transition. K atoms have the smallest hyperfine splitting of the ground levels among alkali metals. 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 circular polarized radiation (σ⁺ or σ^- ), two groups (each consisting of 4) equidistantly located total 8 atomic transitions are recorded in strong magnetic fields. The experimental results are well described by a known theoretical model