March 23, 2021 at 10:06 pm
about the mesh dependence to wavelength: the mesh size depends on min(lambda)/n where n is the refractive index for dielectric materials where loss is not significant.nThe Sellmeier material model can only give you one refractive index without dispersion, since it is mostly used in frequency-domain method, not in time domain. In time domain the material property needs to meet kk relationship, which requires data in imaginary part. In addition, Although this model can be dispersive, FDTD does not treat it as dispersive!nIf you want a dispersive material, you will need create data and then import the data, as a function of wavelength or frequency. please refer https://support.lumerical.com/hc/en-us/articles/360034915093-Creating-new-sampled-data-materials-in-FDTDlet's focus on the huge long simulation time issue: check the memory; test to see if there is strong resonance inside or outside of the interested spectrum from the time monitor. As for the Gaussian beam, after using the default of 200 plane waves, you can use the vectorial one. but before the memory issue is resolved, I suggest to use scalar one in order to isolate the cause of the issues.