Perhaps there is a bug somewhere in your simulation? The following
tutorial example involves computing the reflectance of a planar
interface of air and a wavelength-dependent, lossless material (fused
quartz from the materials library) and validating the results using the
Fresnel equation:
https://meep.readthedocs.io/en/latest/Python_Tutorials/Material_Dispersion/#reflectance-spectrum-of-air-silica-interface
On 11/25/19 15:57, Mckeithen, Dylan M (US 383A-Affiliate) wrote:
Hey Everyone,
I’m trying to model custom materials in meep by fitting Lorentz-Drude
susceptibility parameters to provided n and k values. As a sanity check,
I set up a simulation to measure the reflectivity of a given material,
and I’m comparing this to the reflectivity as calculated using the
Lorentz-Drude susceptibility profile given in the materials_library.py
file. Using Aluminum as an example, I’m finding that the reflectivity in
the meep simulation is higher than expected based on the given material
parameters. The reflectivity calculation is consistent with other
sources for the reflectivity of Aluminum, so I believe there must be a
problem in the simulation. I would expect that calculating the
reflectivity based on LD parameters and simulating a material with those
same LD parameters would give the same answer. I’ve already checked that
the simulation is using the intensity of the fields, so it isn’t a
problem of squaring my simulated reflectivity values. If anyone knows
what might be going on, I would really appreciate it.
Here's a sample of the reflectivity data I’ve collected:
Wavelength (nm) - 500, 600, 700, 800,
850, 900, 1000
Calculated Reflectivity - 0.920, 0.911, 0.904, 0.871,
0.869, 0.895, 0.936
Simulated Reflectivity - 0.963, 0.959, 0.954, 0.936,
0.929, 0.941, 0.964
- - - - - - - - - - - - - - - - - - - - -
Dylan McKeithen
Jet Propulsion Laboratory
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