Micron-thick spectroscopic cells for studying the Paschen-Back regime on the hyperfine structure of cesium atoms

It is shown that the use of spectroscopic cells of micron thickness ( L = 10–50 μm) allows one to effectively study the behavior of individual levels of the Cs D 2 line in strong magnetic fields up to 9 kG. In particular, the absorption spectrum of Cs excited by circularly polarized light in fields above 8 kG consists of two fully separated groups, each containing eight atomic transitions. The intensities of atomic transitions and their frequency slopes (vs. magnetic field) in each group are almost the same. The physical explanation for the observed features is given; in particular, it is shown that one of the 54 possible atomic transitions in moderate magnetic fields (denoted F g = 4, m F = 4 → F e = 5, m F = 5) has unique characteristics that make it possible to predict the intensities and frequency slopes of seven atomic transitions in the same group. Practical applications of devices based on micrometric-thin cells in strong magnetic fields are considered.