Brewster's Angle Calculator
Calculate the polarization angle from refractive indices.
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Enter the refractive index of the incident medium (n1, typically 1 for air) and the transmitting medium (n2). The calculator computes Brewster's angle in both degrees and radians.
About Brewster's Angle
When unpolarized light hits a surface at Brewster's angle, the reflected light is fully polarized in the plane parallel to the surface. This angle depends on the ratio of the refractive indices of the two media. Sir David Brewster discovered this relationship in 1815. The angle satisfies tan(theta_B) = n2/n1. This principle is used extensively in laser optics, photography, and the design of anti-glare coatings.
Frequently Asked Questions
What is Brewster's angle?
Brewster's angle is the angle of incidence at which reflected light is completely polarized. At this angle, the reflected and refracted rays are perpendicular to each other.
How is Brewster's angle used in practice?
Polarizing windows in lasers are set at Brewster's angle to eliminate reflection losses for one polarization. Polarized sunglasses also exploit this principle to reduce glare from surfaces.
Does Brewster's angle depend on wavelength?
Yes, because the refractive index varies slightly with wavelength (dispersion). However, for most practical purposes, Brewster's angle is nearly constant across the visible spectrum.