Third-order hyperpolarizability γ in nonlinear optics

[breezels]

third-order hyperpolarizability "γ" in nonlinear optics

In nonlinear optics third-order hyperpolarizability of molecules "γ" is often measured by THG(third-harmonic generation) experiments.
So third-order nonlinear susceptibility "X(3)" could be calculated from formula using the value of "γ".
Note that third-order nonlinear susceptibility "X(3)" is the complex number.
However in stimulated raman scattering experiments, the gain coefficient "g" is proportion of the imaginary part of X(3).
My question is :
If third-order hyperpolarizability of molecules "γ" is obtained by THG method, can this value("γ" ) be used to calculate the gain coefficient "g" from stimulated raman scattering formula?
or
Is third-order nonlinear susceptibility "X(3)" calculated using the value of third-order hyperpolarizability "γ" by THG method the same with the one used in stimulated raman gain coefficient formula?

 

[breezels]

if the THG signal is close to the resonance absorption-band of some material , the third-order nonlinear susceptibility "X(3)" will become enhanced.

Then for the same material , in stimulated Raman experiments, if the laser frequency is also close to its resonance absorption-band (stimulated resonance Raman scattering), can the third-order nonlinear susceptibility "X(3)" of this material be enhanced?

For cases mentioned above , May third-order nonlinear susceptibilities "X(3)" from the two experiments be the same?or be approximate?

 

[charng]

I understand the importance of accurately measuring and understanding third-order hyperpolarizability in nonlinear optics. This property is essential for predicting the behavior of molecules in response to intense light and is crucial for various applications, such as in optical devices and materials.

In terms of experimental methods, THG experiments are commonly used to measure the third-order hyperpolarizability "γ" of molecules. This value can then be used to calculate the third-order nonlinear susceptibility "X(3)" using a specific formula. However, it is important to note that "X(3)" is a complex number and cannot be directly compared to the gain coefficient "g" used in stimulated raman scattering experiments.

To answer the question, the third-order hyperpolarizability "γ" obtained from THG experiments can be used to calculate the gain coefficient "g" in stimulated raman scattering experiments. However, this calculation involves additional steps and considerations, such as the use of a complex refractive index and the consideration of other factors that may affect the gain coefficient. Therefore, it is not a direct conversion and requires careful analysis and interpretation.

In conclusion, the third-order hyperpolarizability "γ" obtained from THG experiments can be used to calculate the gain coefficient "g" in stimulated raman scattering experiments, but it is important to understand the complexities involved in this calculation and to carefully consider other factors that may affect the results.