# Transmission of polarized light

• Kavorka
In summary: This is called Brewster's angle and at this angle, there is no reflected light.In summary, today's lecture discussed the concept of polarization in light and how it affects the reflection of light when it changes mediums. It was explained that when light is polarized perpendicular to the incident beam, it will always be reflected to some degree. However, when it is polarized parallel to the incident beam, there is a specific angle (known as Brewster's angle) at which it can be transmitted 100% without any reflection. This can be understood through the mathematical derivation of the reflection coefficient and the concept of forced oscillations of electrons. Brewster's angle occurs when the direction of reflection is exactly the same as the direction of incidence,
Kavorka
Today in lecture I learned that when light is polarized up and down (perpendicular to the plane of the incident beam) it is always reflected by some amount upon changing its medium of propagation, but when it is polarized side to side (parallel to the plane of the incident beam), there is an angle at which it can be transmitted 100% (Brewster's angle).

I understand this in terms of the mathematical derivation, each step is understood and you can finally come up with a relation between the reflection coefficient and the incidence angle, and will see that for the perpendicular polarization case the coefficient is never zero, but for the parallel case the graph passes 0% reflection at a certain angle dependent on the indices of refraction.

I am having trouble understanding it conceptually, however, and I feel that I should. My professor said that when you imagine the forced oscillation of the electrons caused by the incident electric field, and then their resulting electric field, you will see by the polarization that the opposing forced electric field can become 0, I assume not its magnitude but it can become perpendicular to the incident electric field. Can anyone help me understand this with an explanation, or a link, or a picture? I'm having trouble understanding why the phase of the reflected light also switches between parallel and perpendicular polarization.

Here is a picture
https://en.wikipedia.org/wiki/Brewster's_angle#/media/File:Brewsters-angle.svg
Basically, the angle of reflection is exactly the same as the angle of incidence. The reflection is caused by the electric field created by the forced oscillations of electrons in the medium. The direction of oscillation is exactly the same as the direction of the electric field in the medium, that is perpendicular to the direction of the light propagation in the medium. When the angle between the direction of reflection and the refracted beam is exactly 90 degrees and the incident EM wave is polarized in the incidence plane, the electrons in the medium move parallel to the direction of reflection. Therefore, the field created by their forced motion has a zero component perpendicular to the direction of the reflection, and cannot induce a transverse EM wave.

blue_leaf77

## 1. What is polarized light?

Polarized light is a type of light that has its electric field oscillating in a single plane. This results in the light waves being aligned in the same direction, giving it a specific polarization direction.

## 2. How is polarized light transmitted?

Polarized light can be transmitted through certain materials that have the ability to selectively filter out light waves that are not aligned with the polarization direction. This allows only polarized light to pass through, resulting in a reduction or elimination of glare or reflected light.

## 3. What is the difference between linear and circular polarization?

Linear polarization refers to the alignment of light waves in a single plane, while circular polarization refers to the spinning motion of light waves in a circular path. Linear polarization is typically used in sunglasses to reduce glare, while circular polarization is commonly used in 3D glasses.

## 4. How is polarized light used in scientific research?

Polarized light is used in a variety of scientific research fields, such as materials science, biology, and chemistry. It can be used to study the structural properties of materials, the orientation of molecules, and the behavior of light in different environments.

## 5. Can polarized light be produced artificially?

Yes, polarized light can be artificially produced using polarizing filters or special light sources. These can be used to control the direction and intensity of polarized light for various applications, such as photography and telecommunications.

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