Optical Bistability with Two-Level Atoms

Since the first observation of optical bistability in 1976, a large number of investigations of this phenomenon have appeared in the literature. Of particular theoretical interest has been the bistable system composed of "two-level" atoms within an optical resonator. While the theory in this case is well-advanced, only recently have experimental results been obtained. The work that we report is for absorptive bistability with an intracavity medium that approximates a collection of two-level atoms. We discuss our measurements of both the evolution of steady-state hysteresis and the slowing down of switching times using an inhomogeneously broadened medium in a standing-wave cavity. We also present results of the first observation of absorptive bistability in a predominantly homogeneously broadened medium of two-level atoms in a ring cavity.