Introduction to Nonimaging Optics, 2nd Edition

16

Reflection and Refraction

16.1 Reflected and Refracted Rays

A ray i traveling in a medium of refractive index n₁ incident on a surface A with normal n is refracted thereupon into a medium of refractive index n₂. The angle α₁ that the ray makes with the normal before refraction is related to the angle it makes with the normal after refraction, by Snell’s law of refraction:

n1sinα1=n2⁢sinα2R⁢(16.1)

Note that expression (16.1) for a refracted ray can also be written as

which is equivalent to a refraction from a medium of refractive index n_A = 1 into another medium of refractive index n_B = n₂/n₁. In that case, expression (16.2) can be ...