I am running simulations with laser gain medium modeled using 4-level 2-electron material system. I have selected a base material of refractive index 1.5 (dispersionless) for that gain medium.
However, I have noticed from the results of non-linear simulations using this material that real part of refractive index of the gain medium shows dispersion around the resonant frequencies. Is there any way to plot the variation of real part of the gain medium as a function of frequency ? Such plots are not accessible for gain mediums through material explorer in Lumerical.