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 >. For each circular polarization (,), four spectrally resolved atomic transitions having sub-Doppler widths are recorded using a sub-microsized vapor cell of thickness =120-390. We present a method that allows to measure the magnetic field in the range of 0.1-10 with micrometer spatial resolution, which is relevant in particular for the determination of magnetic fields with large gradients (up to 3 G/µm). The theoretical model describes well the experimental results.