Absorptive optical bistability in two-state atoms

The standard theoretical model of optical bistability assumes a medium consisting of a collection of two-state atoms interacting with a single mode of an optical cavity. Our purpose in this contribution is to give a summary description of our experimental and theoretical investigations of the steady- state regime in absorptive bistability in an experimentally realistic system that closely approximates a collection of radiatively broadened two-state atoms interacting with a single Gaussian-profile cavity mode. We have performed an experiment in which all relevant parameters are measured precisely and have carried out an analysis which is an extension of the standard two-state theory as required in order to permit absolute quantitative comparisons with our experiment. While we have previously reported our measurements, the results we discuss here include improvements on the experimental techniques of our earlier report: better stability of the laser and the optical cavity, improved calibration procedures, and investigation several times farther beyond the threshold for onset of bistability. We also describe here, for the first time, results from a rather extensive theoretical analysis including better treatments of finite absorption, cavity properties, and transit broadening