# Is the polarization of light relative?

• Nirgal
In summary, the measured polarization of a beam of light relative to the frame of the observer is relative.
Nirgal
I was wondering if anyone had input into this question. Is the measured polarization of a beam of light relative to the frame of the observer?

In the texts on Optics that I've read, there does not seem to be any reference to the observer's frame. It is only mentioned that light is Left-circularly polarized or linearly polarized, etc.

When we describe polarization we ascribe to the light-beam in question a vector representing the polarized state. But is that polarized state the same for each observer?

I am speculating that the polarization is relative and this is my (naive) reasoning.
If we were discussing the path of a bullet, then in the frame of reference of somebody rotating, the path of the bullet would be curved. So the time dependent vector representing the path of the bullet would depend on the frame of reference of the observer.

Now, the physics of light is so bizarre and I can barely understand it that I do not assume that the analogy between bullets and light can be taken very far. The point of the analogy though is that polarization state is described by a vector and similarly the path of the bullet. And since the mathematical abstraction that the vector represents depends on the reference frame for the bullet then I would assume that the polarization similarly depends on the reference frame of the observer as well.

This is one of my problems in physics though. I am constantly in a wrestling match between distinguishing the mathematics from the physics.

First consider the case of a massive spinning particle. Say that one observer says the particle is spinning like a right-handed screw going into a piece of wood, i.e., clockwise as seen from behind. Another observer who is traveling in the same direction as the particle, but faster, sees the particle as going backward, and therefore says it is spinning like a left-handed screw.

It's different in the case of a massless particle. You can't overtake a massless particle, because massless particles travel at c.

This is also why it's possible to have a law of physics that says that light is always transversely polarized. You can't have a constraint on the polarization of a massive particle, because there would be no way to define the constraint in the frame where the particle was at rest.

bcrowell said:
First consider the case of a massive spinning particle. Say that one observer says the particle is spinning like a right-handed screw going into a piece of wood, i.e., clockwise as seen from behind. Another observer who is traveling in the same direction as the particle, but faster, sees the particle as going backward, and therefore says it is spinning like a left-handed screw.

It's different in the case of a massless particle. You can't overtake a massless particle, because massless particles travel at c.

This is also why it's possible to have a law of physics that says that light is always transversely polarized. You can't have a constraint on the polarization of a massive particle, because there would be no way to define the constraint in the frame where the particle was at rest.
I suppose you mean massless.

Passionflower said:
I suppose you mean massless.

No, I meant massive.

bcrowell said:
No, I meant massive.
Oh I see, you are talking about a constraint, took me a second the realize what you wrote.

Sorry for that.

## 1. What is the concept of polarization of light?

The polarization of light refers to the direction in which the electric field of a light wave oscillates. This direction is perpendicular to the direction of the light wave's propagation.

## 2. Is the polarization of light relative to the observer?

Yes, the polarization of light is relative to the observer's perspective. This means that the direction of polarization can vary depending on the orientation of the observer relative to the light wave.

## 3. Can the polarization of light be changed?

Yes, the polarization of light can be changed by passing it through certain materials or by manipulating its path through a polarizing filter. This process is known as polarization manipulation.

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

Linear polarization refers to light where the electric field oscillates in a single plane, while circular polarization refers to light where the electric field rotates in a circular motion. Linear polarization can be thought of as a special case of circular polarization where the rotation is either full (horizontal) or half (vertical).

## 5. How is the polarization of light relevant in everyday life?

The polarization of light has many practical applications, such as in 3D glasses, LCD screens, and polarized sunglasses. It is also important in understanding the behavior of light in various materials and in certain natural phenomena, such as the polarization of light by the Earth's atmosphere.

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