How to understand the refractive index of metals

[zhanghe]

for an example, polycrystalline silver, its index is n=0.135 and k =3.999 at the wavelength of 633nm, what does the nk mean, is that telling us the wavelength in the silver equals 633/0.135 nm ? and how to calculate the refractive angle in the metal?
Give a good explanation, please.

 

[Dr Transport]

Silver is a metal, which has a skin depth, after which the incident radiation does not penetrate any further. Look in the later chapters of Born & Wolf, Principles of Optics in the chapter about optics of metals. The refractive index is a complex quantity in metals because of absorption.