MaterialGrid for LorentzianSusceptibility materials

[yungchiang]

Hello Meep community,

According to the Meep document, LorentzianSusceptibility type materials are supported in MaterialGrid class. However, after doing many times of try and error, I still found that only the epsilon parts are interpolated and the E_susceptibilities are completely ignored. And the geometry region using the MaterialGrid material showed that it is just a pure dielectric material not a LorentzianSusceptibility material. (I have read the code “meepgeom.cpp” and found that sigma_diag and sigma_offdiag are interpolated in the code.) I can find some examples that use MaterialGrid for two dielectric materials in Github. But I can’t find any example for MaterialGrid with two LorentzianSusceptibility materials. Can anyone provide a simple example for MaterialGrid using LorentzianSusceptibility materials? Thank you for your help.

[stevengj]

You probably need to add the susceptibilities to extra_materials (see the Simulation constructor).

[yungchiang]

Thank you for your help. After adding extra_materials, MaterialGrid for LorentzianSusceptibility materials is normal now.

[kannesito]

Hi there,
a follow-up question: What happens, if one of the two materials/mp.medium (or maybe even both media) in MaterialGrid has (have) a D_conductivity specified? Will the medium with the conductivity retain its conductivity value? 'Cause that would mean, a 3D material of arbitrary shape and Permittivity + D_conductivity could be initialized in the cell, while the second medium could be vacuum or mp.air, do I get this right?
Thanks in advance!