Bright magneto-optical resonance sign reversal in Cs vapour confined in an extremely thin cell

An extremely thin cell (ETC) was used to analyse ground state effects of Cs atoms excited by laser light and placed in a magnetic field that was scanned around zero. The advantage of using the ETC is the possibility to separate the hf transitions, which are overlapped in ordinary cells, as a result of the spatial anisotropy of the atom-light interaction. Cs atoms were irradiated by circularly/linearly polarized light at lambda~852 nm, and the dependence of absorption on the external magnetic field was measured.