Optical Constants

Abstract

In the chapters on geometrical optics, interference, and electromagnetic theory we have sometimes used the refractive index n = c/υ. When light enters a dielectric medium, it interacts with the atoms and changes its speed from c in vacuum to y in the medium. The medium is called isotropic when the speed of light is the same in all directions. The refractive index may be obtained from the real part of the dielectric constant in Maxwell’s equations. In the case where there are losses in the medium, light will be absorbed, and one uses the complex dielectric constant in Maxwell’s equations.