On 07/18/2018 10:47 AM, Vince Lee wrote:
I'm new to Meep. I've installed pymeep and I'm running some of the tutorial examples. I have a question about the material library mentioned here (https://meep.readthedocs.io/en/latest/Materials/). The material library (https://github.com/stevengj/meep/tree/master/python/examples/materials_library.py) has Silicon but it only covers a wavelength range of 1.36 - 11 um, which misses the 1~1.4 um range I'm interested in. From the reference website https://refractiveindex.info/?shelf=main&book=Si&page=Salzberg there're many other models that covers that range, but I don't know how to get the necessary parameters to build the Lorentzian susceptibility profile of my own.
The fitting parameters in the materials library are all based on published references. Silicon has an indirect bandgap at approximately 1.12 eV (wavelength of 1.1 um) at T=300K which makes fitting to a Drude-Lorentz susceptibility profile particularly challenging (the complex part is nearly negligible over a broad bandwidth). Note that the Salzberg reference included in the materials library is based on the Sellmeier coefficients which is valid for only a real permittivity and can be readily converted into Drude-Lorentz form by setting γ=0.
Perhaps you can find a reference which has the fitting parameters over the missing wavelength range or try doing the fit on your own?
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