# Brewster's angle and the intensity of reflected light

• PainterGuy
In summary, at Brewster's angle, all incident light with an electric field parallel to the plane of incidence is fully refracted, while the portion of light with an electric field perpendicular to the plane of incidence is split between being reflected and refracted. Under ideal conditions, the proportions of reflected and refracted light can be calculated using the Fresnel Equations. However, at Brewster's angle, the portion of light with an electric field perpendicular to the plane of incidence is minimized in the total amount of refracted light.
PainterGuy
Hi,

Would it be correct to say that at Brewster's angle, all the incident light which has its electric field parallel to the plane of incidence gets refracted, and the rest of light whose electric field is perpendicular to the plane of incidence gets reflected? For example, if the light whose electric field is parallel to the plane of incidence contributes 70% towards the intensity of light then at Brewster angle, the reflected light has intensity of only 30%. Could you please help me with it?

The "all the incident light which has its electric field parallel to the plane of incidence gets refracted" is correct.
The "and the rest of light whose electric field is perpendicular to the plane of incidence gets reflected" is not correct.

Some of the light with an electric field perpendicular to the plane of incidence will also be refracted.

In the example you gave:
The 70% that is parallel will be fully refracted.
The 30% that is perpendicular will be split - with most of it being reflected.

PainterGuy
.Scott said:
The "and the rest of light whose electric field is perpendicular to the plane of incidence gets reflected" is not correct.

Thank you!

Wouldn't it be correct in an ideal case?

No.
Under "ideal" conditions, the proportion of light reflected and refracted can be computer by using the Fresnel Equations.

PainterGuy
Thank you.

I think that it could be rephrased as follows.

At Brewster's angle, all the incident light which has its electric field parallel to the plane of incidence gets refracted, and all the reflected light has its electric field perpendicular to the plane of incidence. The refracted light would consist of both 'types' of light, but at Brewster's angle the portion of light whose electric field is perpendicular to the plane of incidence is at its minimum in the total of refracted light.

.Scott and vanhees71

## What is Brewster's angle?

Brewster's angle, also known as the polarizing angle, is the angle at which light waves that are incident on a surface are completely polarized. This means that the reflected light will be completely polarized, with the electric field vector of the light waves oscillating only in one direction.

## How is Brewster's angle related to the intensity of reflected light?

At Brewster's angle, the intensity of reflected light is at its minimum. This is because the reflected light is completely polarized and only a small portion of the incident light is reflected. The rest of the light is either absorbed or refracted.

## What factors affect Brewster's angle?

Brewster's angle is affected by the refractive indices of the two media at the interface and the angle of incidence. It also depends on the polarization state of the incident light, as only light waves that are polarized parallel to the plane of incidence will be completely polarized at Brewster's angle.

## Can Brewster's angle be observed with all types of light?

No, Brewster's angle can only be observed with light that is polarized parallel to the plane of incidence. This means that unpolarized light or light that is polarized perpendicular to the plane of incidence will not exhibit the minimum intensity of reflected light at Brewster's angle.

## What are some real-world applications of Brewster's angle?

Brewster's angle has many practical applications, such as in polarizing filters for sunglasses and camera lenses, as well as in optical devices like polarizing beam splitters and polarizing prisms. It is also used in the study of materials and surfaces, such as in ellipsometry, to determine the refractive index and thickness of thin films.

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