Dynamics of Optical Bistability in Sodium and Transient Bimodality

This paper deals with experiments on a Fabry-Perot resonator filled by sodium atoms in a buffer gas atmosphere (Fig. 1a). The pressure broadening predominates the Doppler broadening and the hyperfine splitting in the sodium ground state. As a consequence the model of homogeneously broadened two-level atoms might be thought to be a good approximation. The spin of the sodium atoms, however, still has to be taken into account and it actually plays a crucial role in the experiments to be discussed here.