We present a formalism to incorporate high order effects of the pump field on the fourwave mixing signal for a two-level system immersed in a thermal bath. We derive analytical expressions for the nonlinear polarization in terms of the field amplitude and thermal noise parameters
In this work, we analyze different levels of propagation of the Four-wave mixing signal in a strongly driven two-level system when the stochastic effects of the thermal bath, are considered. First approximation level, given by an analytical solution valid only for constant pump intensity along the optical path; a second approximation level as an analytical solution valid for a lineal variation of the pump intensity, and finally, a third level as numerical solution, which represent the exact case. In all cases, high dependence of the nonlinear propagation with the chemical concentration, stochastic noise parameters, relaxation times, are studied.
This work studies the spatial propagation of the four-wave mixing signal of a molecular system with two electronic levels immersed in a thermal bath. Using the optical Bloch-Maxwell equations, we present three approximations, two of them are analytical solutions and the other is a numerical approach, where the effects of the variation of pump intensity through the optical path are considered. Also, we compare these results with the analogous in absence of the thermal reservoir and it is shown that the stochastic effect induced by the solvent, due to the experimental conditions as relaxation times, concentration of the solution and optical frequencies of the pumps, diminishes the intensity responses compared with the same in absence of the bath.
This work studies the spatial propagation of the Four-Wave Mixing (FWM) signal of a molecular system (malachite green) with two electronic levels immersed in a thermal bath, under a perturbative treatment at all order in the pump field and to first order in the probe and signal fields.Using the Optical Stochastic Bloch Equations OSBE, we present three approximations, two of them with analytical solutions and the third with a numerical approach, where the effects of the variation of pump intensity through the path optical are considered.We compare these results with the analogous in absence of the thermal reservoir.The stochastic effects induced by the solvent, due to the experimental conditions as relaxation times, chemical concentration of the solution and optical frequencies of the fields, diminishes the intensity responses compared with the same in absence of the bath.
Considering an electronic two-level system coupled to vibrational degrees of freedom and driven by short and intense non-overlapping laser pulses, we introduce the concept of nonperturbative response functions. These response functions are expressed in terms of effective electronic transition dipole moments which depend on the strength of the field-matter coupling and on the pulse durations. It is shown that the nonlinear polarization representing four-wave-mixing signals can elegantly be expressed in terms of these nonperturbative response functions to all orders in the field-matter coupling. The nonperturbative response functions generalize the interpretative power of the familiar third-order response functions to four-wave-mixing experiments with intense laser pulses.