<title>Three-photons absorption as a regulator of Kerr's effect strength in ring interferometer: a model and regimes analysis</title>

Abstract

As it is known the optical Kerr's effect changes cubic medium refraction index and in a nonlinear ring interferometer (NRI) causes to generation of optical structures and chaos. Besides in nonlinear media enough high emission power stimulates a multiphoton process. For example in a cubic medium three-photon absorption is possible. The process in a ring interferometer containing Kerr's medium through which the two-frequency light field is propagated are considered. The influence of mulitiphoton processes to dynamics of nonlinear phase shift in Kerr's medium is investigated. The mathematical model is constructed as differential partial equation, ordinary differential equation, discrete map. Maps of Lyapunov's characteristic exponents as functions of the interferometer and light field parameters are constructed. The influence of these parameters to possibility of determined chaos is discussed. It is shown that the act of three-photons absorption (N=3) produces an amplification of nonlinear effects in NRI due to generation of the third harmonics. And the position of the obrder of nonlinearity is determined by a value K_{b0 s} which is proportional to [2β_bl(N-1)]^-1/(N-1), where l is length of the medium, β_b is a measure of three harmonics generation productivity.