Nonlinear Optical Phenomena with Finite Memory Effects

抄録

Several nonlinear optical phenomena are described exactly for two-level electronic systems with a Gaussian frequency modulation under a pump field of arbitrary strength. We discuss the emission spectrum and the absorption spectrum of weak probe field under pumping in the frequency region, and the free induction decay (FID) and the optical nutation (ON) as examples of the coherent optical transients in the time region. It is shown that the relaxation behavior depends upon the pumping field intensity, i.e., the effect of the frequency modulations is reduced when the Rabi frequency increases beyond the amplitude or the inverse correlation time of the frequency modulation. We further show that the relaxation behavior depends upon the particular nonlinear optical phenomena, i.e., the vertex correction due to the frequency modulation works in the FID but does not in the ON.