Brewster's Angle Calculator with Fresnel Reflectance

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Choose a preset material for the medium the light travels through, or select Custom to type in any index.
Choose a preset material for the reflecting medium, or select Custom to type in any index.
Turn on to enter any angle of incidence and see Rs, Rp, and transmittance at that angle.
Brewster's angleTypical optical interface
56.3deg

Angle of incidence at which reflected light is completely p-polarized (Rp = 0)

Refraction angle at Brewster angle33.7deg
Rs at Brewster angle14.77%
Rp at Brewster angle0%
Degree of polarization100%
56.3 deg
Very low (n2/n1 < 0.58)<30Low (n2 < n1)30-45Typical (air-to-glass range)45-60High (air-to-dense glass)60-75Very high (air-to-diamond)75+

Brewster's angle is 56.30 deg for this air / glass interface.

  • At Brewster's angle (56.30 degrees), the reflected ray and refracted ray are perpendicular to each other - the reflected angle plus the refracted angle equals 90 degrees.
  • The s-polarized (TE) reflectance at this angle is 14.77%, meaning 14.77% of s-polarized light is reflected while 0% of p-polarized light is reflected.
  • The refracted ray travels at 33.70 degrees from the surface normal inside the glass medium.
  • Light travels from a lower-index medium (air) into a higher-index medium (glass), so Brewster's angle is greater than 45 degrees.

Next stepPolarizing filters for cameras and sunglasses exploit this effect: orienting the filter to block p-polarized reflected light eliminates most glare from flat surfaces like water and glass.

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