Raman model allows another way to simulate the nonlinear phenomenon where the
nonlinear susceptibility was modeled by a second-order derivative equation which is
related to the resonant wavelength and the response time
where
| εL | is the linear relative permittivity |
| XNL | is the nonlinear susceptibility |
| τ | is the response time |
| εR | is Raman model permittivity |
| ωR | is the Raman model resonant frequency |
In order to simulate the Raman effect, set four parameters for Raman model: εL, εR,
τ, and ωR.