Silicon is the second-most common element on Earth. It forms the basis of nearly all non-optical semiconductor devices. Optically, silicon is most interesting as a detector or reflector, where its refractive index and extinction coefficient are of primary importance.

The refractive indices tabulated below apply whether the 111 or 100 crystal plane is exposed to the sample surface. Dopant levels also have a very small effect on the index of refraction in the wavelength ranges considered here (200 to 2500nm). Silicon forms a nearly-ideal surface layer of SiO2 when exposed to oxidizing environments. The "native" oxide layer that forms in typical ambients must often be taken into account when measuring the thickness or refractive index of very thin films on silicon.

For a typical sample of Si the refractive index and extinction coefficient at 632.8 nm are 3.88163 and 0.01896923. Below are files of complete refractive index and extinction coefficients. If the file is not available for download, you can request our proprietary file by clicking "Request".

Refractive Index Reference - Handbook of Optical Constants of Solids, Edward D. Palik. Academic Press, Boston, 1985

No guarantee of accuracy - use at your own risk.