 # What is polarization by reflection and brewster�s law?

We know from Ray optics when a light is incident on the surface of transparent medium of refractive index (μ), some light gets reflected other gets refracted, from Snell’s law as we increase the incident angle the angle of refraction also increases and from law of reflection

Angle of incidence = angle of reflection

When angle of incident i = ip

The reflected ray and the refracted ray will be perpendicular to each other then the reflected Light is completely plane polarized this angle (ip) is known as angle of polarization.

Brewster’s Law statement

When angle of incident is equal to angle of polarization, the reflected ray and refracted ray will be perpendicular to each other.

From Snell’s law

$$\begin{array}{l}mu =frac{sin i}{sin r}=frac{sin {{theta }_{p}}}{sin {{theta }_{r}}}\end{array}$$

Since reflected ray perpendicular to refracted ray 90° + p + r = 180°

$$\begin{array}{l}{{theta }_{r}}=90{}^circ -{{theta }_{p}}\end{array}$$

$$\begin{array}{l}mu =frac{sin {{theta }_{p}}}{sin (90{}^circ -{{theta }_{p}})}=frac{sin {{theta }_{p}}}{cos theta {}_{p}^{{}}}\end{array}$$
b

$$\begin{array}{l}mu =tan {{theta }_{p}}\end{array}$$
is known as Brewster’s Law (8) (2)