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Metal permittivity

Posted: Tue Sep 26, 2017 11:01 am UTC
by Minerva
Given a known bulk plasma frequency (say 3.7 PHz for aluminium), and a known incident wavelength (say 500nm), what's the expression for the relative permittivity of the metal?

For context, consider a plasmonic device that acts as a filter, with a nanoscale grid of holes in metal.

The maximum transmission wavelength at normal incidence is given by lambdamax = (a / sqrt(i2 + j2)) * sqrt((Em * Ed) / (Em + Ed))

Here, Em is the metal permittivity of interest, Ed is the permittivity of the dielectric substrate, say 4(ish) for SiO2.
(a is the lattice spacing.) ... al-imaging