Dispersion Implementation

[ymahlau]

In the current implementation of FDTDX, only permittivities and permeabilities for a single wavelength is supported. To support accurate modelling of materials with changing refractive indices at different wavelength an implementation of dispersive materials is needed.

We think that an implementation of the Lorentz-model would be most useful, but we are open to suggestions if community member have other ideas.

Regarding implementation the additional parameters of the Lorentz model would need to be stored in the arrays container. This would lead to higher memory usage, so the dispersive simulation should be an optional flag.

We also encourage contribution to the implementation if community members are interested!

[txdai]

I would suggest implementing this like Tidy3D's "Custom Pole Residues" functionality

[ymahlau]

This is a really good suggestion, I was not aware of this functionality!