Absorptive and dispersive optical profiles in fluctuating environments: A stochastic model

In this study, we determined the absorptive and dispersive optical profiles of a molecular system coupled with a thermal bath. Solvent effects were explicitly considered by modelling the non-radiative interaction with the solute as a random variable. The optical stochastical Bloch equations (OSBE) were solved using a time-ordered cumulant expansion with white noise as a correlation function. We found a solution for the Fourier component of coherence at the third order of perturbation for the nonlinear Four-wave mixing signal and produced analytical expressions for the optical responses of the system. Finally, we examined the behaviour of these properties with respect to the noise parameter, frequency detuning of the dynamic perturbation, and relaxation times.

Research highlights► Frequency fluctuations induced by the solvent are described stochastically. ► Nonlinear optical properties are more sensitive to the transversal relaxation time. ► Noise parameter is related to the solute-solvent coupling. ► As the noise parameter increased, nonlinear optical properties weakened.