What happens if I have a rotating half-wave plate?

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Discussion Overview

The discussion centers on the behavior of unpolarized light passing through a rotating half-wave plate, particularly at a frequency of 1 Hz, and the resulting effects when a linear polarizer is placed downstream. The scope includes theoretical considerations of polarization and optical properties of materials.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant inquires about the effects of rotating a half-wave plate on unpolarized light from a laser.
  • Another participant seeks clarification on the definition of "natural light," leading to a specification that it refers to unpolarized light from a laser.
  • A further contribution explains that unpolarized light can be modeled as randomly varying linearly polarized light, suggesting that the half-wave plate will rotate the polarization direction without changing the intensity of the light.
  • This participant questions whether the polarization state and intensity of the incoming unpolarized light will change due to the random nature of its polarization states when the half-wave plate is rotated.

Areas of Agreement / Disagreement

Participants have not reached a consensus, and multiple viewpoints regarding the effects of the rotating half-wave plate on unpolarized light remain present.

Contextual Notes

The discussion does not address potential limitations or assumptions regarding the behavior of light or the specific characteristics of the half-wave plate and polarizer setup.

Who May Find This Useful

This discussion may be of interest to those studying optics, polarization phenomena, or anyone exploring the properties of light in experimental setups.

Corwin_S
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Hey there,

What would happen if I had a half-wave plate, and I rotated it at like 1 Hz? If I stick a linear polarizer on the other end, what would my outcoming beam look like if the incoming one was natural light?
 
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What do you mean by natural light?
 
Sorry. Unpolarized light from a laser.
 
Unpolarized light can be modeled as a randomly varying linearly polarized light, i,e, take a snapshot of the wavefront you will see it is polarized in one direction, take another snapshot at different time you will see it's polarized in another direction, it's just that there is no fixed relationship connecting the polarization states at different times. Now a half-wave plate is pure rotator, it only rotates the polarization direction of a linearly polarized light but keeps the intensity constant. If you let your unpolarized light pass through a half-wave plate, obviously the outgoing light will also be unpolarized without change in intensity because at every instant of time the polarization of an incident wavefront is just rotated. If you rotate the half-wave plate with a certain rate, do you think the polarization state as well as the intensity of an incoming unpolarized light will change given the random nature of the polarization state?
 

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