We have experimentally investigated the dynamical hysteresis cycles in the optical bistability from the vapor of rubidium atoms contained in an optical cavity by changing the sweeping frequency of the input cavity field. The shape, width and direction of the hysteresis cycle are sensitive functions of the sweeping frequency parameter.
We have experimentally observed a ``backward'' (clockwise rotating) hysteresis cycle in the system of an optical ring cavity containing three-level ($\ensuremath{\Lambda}$-type configuration) rubidium atoms. The shape and direction of the observed hysteresis cycles can be easily controlled with experimental parameters. Such an interesting phenomenon is caused by the greatly modified absorption, dispersion, and nonlinear optical properties of the three-level atomic medium, due to the induced atomic coherence.
We theoretically investigate the optical bistability phenomenon in an ensemble of N non-interacting three-level atoms trapped inside an optical cavity. The atoms are in a Λ-level configuration, where one atomic transition is coupled by a cavity mode, while the other one is coupled by a classical field. In addition, we consider a pumping field driving the cavity mode. With this system, we are able to observe new kinds of hysteresis, while scanning either the frequency of the pumping field or the Rabi frequency (intensity) of the control field. We show that they can be highly controllable via external parameters of the system, achieving very narrow widths, thus being very useful for building new devices, such as small fluctuation detectors in either frequency or intensity of laser fields.