Refractive Index

Warning

This page is INCOMPLETE

The refractive index is a dimensionless number that gives an indication of how much light will bend in a medium.

While we typically deal with a real-valued refractive index, many materials have a complex refractive index which, where the real part is the standard refractive index, and the imaginary part is known as the optical extinction coefficient. Vacuum will have a perfectly real refractive index of 1, while something like glass will have a very small extinction coefficient. Metals have a very large extinction coefficient due to them being a conductor (and thus absorb incident electromagnetic waves extremely well as their free elections are free to oscillate with the incoming wave).

Snell’s Law

\[n_1 \sin{\theta_1} = n_2\sin{\theta_2}\]

where \(\theta_1\) is the angle of incidence, and \(\theta_2\) is the angle of refraction (both relative to the surface normal at the interface).