treams.Material.from_nmp

classmethod Material.from_nmp(ns=(1, 1), impedance=None)

Create material from refractive indices of both helicities.

This function calculates the relative permeability and permittivity and the chirality parameter with \(\epsilon = \frac{n_+ + n_-}{2Z}\), \(\mu = \frac{(n_+ + n_-)Z}{2}\) and \(\mu = \frac{(n_+ - n_-)}{2}\).

Note

Two refractive indices are defined here that depend on the chirality parameter. For an alternative definition of the refractive index, see also Material.from_n().

Parameters:
  • ns ((2,)-array-like, optional) – Negative and positive helicity refractive index. Defaults to (1, 1).

  • impedance (complex, optional) – Relative impedance. Defaults to the inverse of the average refractive index.

Returns:

Material