Analysis of the stochastic effects of the solvent and high-pump-power on the nonlinear optical properties in four-wave mixing spectroscopy

Using the Optical Stochastic Bloch equations (OSBE), and considering a two- level molecular system interacting with a thermal reservoir (modeled as an Ornstein-Uhlenbeck process) in four-wave mixing spectroscopy, we derive ana lytical expressions for the nonlinear optical properties (absorptive and di spersive processes). Here, we have widened the previous formalism [(J.L, Pa t et al,, Phys, Lett, A 226 (1997) 365)] to consider the solvent effects an d high-pump-power in the four-wave mixing (FWM) technique. The saturation e ffects introduced by including high-pump-power are explicitly considered. T hese results are very useful when laser-beams of moderate or high-intensity are employed for the determination of relaxation mechanisms in molecular s ystems interacting explicitly with their environment. (C) 1999 Elsevier Sci ence B.V. All rights reserved.