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Reflection and refraction

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Reflection and refraction diagram
calc
The Fresnel equations and Snell's law are used to calculate the reflection and refraction that occurs at an interface of two materials when light falls on it at a given angle. Brewster's angle and the angle of total internal reflection (critical angle) are also given (as appropriate).
Index a
Index b
Angle α

Angle β
Reflection (s)
Reflection (p)
Brewster's angle
Critical angle
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notes
Enter the refractive indices of the materials a and b, and the angle (to normal) of the beam in material a. For reference, at 589 nm air has an index of ~1.0003, water of 1.33, acrylic of 1.48, glass of ~1.5, polycarbonate of 1.6, and diamond of 2.4. Refractive index is wavelength-dependant.
The calc gives the (refracted) angle in material b, the reflection of the two different polarizations (p is in the plane of the diagram), as well as Brewster's angle and the angle of total internal reflection (if appropriate).