The Study Of Optical Bistability In Multi-level Atomic System

Quantum interference is a quantum phenomenon that totally different with classicalinterference, It is described that the same quantum system with several not homomorphism isadded into a pure state. It has a very important value and the significance of the studying onoptical bistability in the quantum interference medium. Compared with three-level atomicsystem of two energy level system is one of the most important advantage is the nonlinearmedium atoms as into the optical cavity can be induced by the use of atomic coherence, thiswould enable the absorption, dispersion and nonlinear properties of three level system arechanged so that the optical bistability phenomenon more obvious, and we can understand betterthe nature of optical bistability and the influence factors.Two different structural models of optical bistability was studied. By using the densitymatrix method, the effect of each parameter on optical bistability are investigated in detail. Thespecific content is follow:(1) The background, research status and related phenomena of this paper is introduced(2) The description of three pictures of the quantum system, semiclassical theory of theinteraction of light with matter, is mainly described. The density matrix equation is deduced indetail, and describes the basic theory of optical bistability of research methods.(3) The density matrix method is using to study the phenomenon of three-level Λ-typeactive Raman gain medium optical bistability (OB)driven by two laser fields in a unidirectionalring cavity. We can control and change the optical bistability clearly by change the addedparameters such as the frequency of pump and control field, electron concentration, detuningand so on. Besides, we give the range of these parameters for realizing OB, and these canprovide some extent theoretical basis for experimental realization.(4) This paper studied the behavior of the tripod type four level atomic medium is drivedby three light fields in resonant system, then put it to the unidirectional ring cavity. Through thestudy we found that the driving field and control field frequency, the cooperation parameters,and the detuning can influence the produce of optical bistability in different degree. Thebistable threshold width and adjustable parameters are given, it can provide a theoretical basisfor experimental control and realization of optical bistability.