The index of refraction of a material is the ratio of phase velocity of an electromagnetic wave in free space to the phase velocity in the material. The extinction coefficient is the imaginary part of the index of refraction.
These optical constants are calculated via linear interpolation on the optical constant values reported in Handbook of Optical Constants of Solids by Edward D. Palik. The graphs and numerical data can be found on the Tabulated Optical Constants page.
Choose a material, enter the incident wavelength, and click Calculate. The material's index of refraction and extinction coefficient will appear below.
All wavelengths are entered in nanometers.
