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Complex Index of Refraction Lookup Utility

Complex Index of Refraction Look-up Utility

Index of Refraction Explanation

The Index of Refraction of a material is the ratio of phase velocity of an electromagentic wave in free space to the phase velocity in the material. The index of refraction of two materials can be used to predict how light will pass from one medium to the other. 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 the book 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 from the drop down menu, enter the incident wavelength, and click on "Calculate." The material's index of refraction and extinction coefficient will appear below.

Incident Wavelength: (in nanometers)
Material Index:
Material Extinction Coefficient
Error message: