CHAPTER 2 - STEADY-STATE MODEL OF OPTICAL BISTABILITY

Abstract

This chapter describes the Bonifacio–Lugiato model of optical bistability. It describes nonlinear properties of a two-level atom subjected to a coherent field. From the boundary conditions of the light interacting with the etalon and from the saturation equations of a homogeneously broadened two-level system, an inequality that must be satisfied for bistability to occur is derived. A trade-off between cavity finesse and absorption is found. The Szoke et al. model of absorptive bistability is analytic. The model of purely dispersive bistability can be extended to include many more details such as standing-wave effects, nonlinear absorption, medium complexities such as many transitions on and off resonance, and inhomogeneous broadening. Hybrid Fabry–Perot resonator with electrical feedback to an intracavity electro-optic phase shifter is used to produce electrical instabilities or to stabilize the intensity of a light beam. In dispersive bistability, the Fabry–Perot peak is shifted relative to fixed absorber and laser frequencies. In increasing absorption bistability, the absorption is shifted relative to the fixed laser frequency. Multi-stability cannot occur for increasing absorption bistability, although kinks involve multiple spatial states. Increasing absorption optical bistability might also be called photodarkening bistability or self-induced darkness bistability or self-induced opaqueness bistability.