Optical properties of metals in the MIR

Hi All,

I am simulating gold nanostructures that, because of their geometry, are expected to have a plasmonic resonance in the MIR (aprox. 4 microns).

I am using models from nanohub to get the optical properties of gold (real and imaginary parts of epsilon). But all these models are inaccurate >2micron.

What can I do?

Thanks in advance!

Ramses