Units of pole data in python/materials.py

[TimOfAllTrades]

I had a question about some of the values in materials.py.

When using the Lorentz Drude model, I have an understanding that each pole had a proportionality constant * plasma frequency (usually merged into a single constant), a resonance frequency, and a damping constant.

The units I am normally used to working with are radians per second for each of those 3 values.

cSi_frq1 = 3.64 / um_scale
cSi_gam1 = 0
cSi_sig1 = 8
cSi_frq2 = 2.76 / um_scale
cSi_gam2 = 2 * 0.063 / um_scale
cSi_sig2 = 2.85
cSi_frq3 = 1.73 / um_scale
cSi_gam3 = 2 * 2.5 / um_scale
cSi_sig3 = -0.107

I see in the materials.py file, there is a frqN, gamN, and sigN with various values. Do those 3 correspond to the quantities I mentioned earlier? How do you convert the materials.py values into units of Rad/s?

Thank you and best regards

[smartalecH]

As discussed in the docs, meep internally multiplies by $2\pi$ where needed. So don't specify your coefficients in terms of radians.

It's also not correct to universally use "seconds" either unless your length scale dictates that (see discussion in docs)

You can use the information above to map to an arbitrary unit.