Wide range linear magnetometer based on a sub-microsized K vapor cell.

atoms have the smallest ground state () hyperfine splitting of all the most naturally abundant alkali isotopes and, consequently, the smallest characteristic magnetic field value =/≈170, where is the ground state's magnetic dipole interaction constant. In the hyperfine Paschen-Back regime (≫, where is the magnitude of the external magnetic field applied on the atoms), only eight Zeeman transitions are visible in the absorption spectrum of the line of , while the probabilities of the remaining 16 Zeeman transitions tend to zero. In the case of , this behavior is reached already at relatively low magnetic field >.