Complete annihilation of light through polarizers

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Discussion Overview

The discussion revolves around the behavior of light when passing through two crossed polarizers, specifically addressing the observation that complete darkness is not achieved, and instead, the light source appears to change color rather than becoming completely black.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant notes that they do not observe complete darkness when viewing a light source through crossed polarizers, instead seeing a change in color (e.g., dark blue instead of black).
  • Another participant suggests that the polarizers are imperfect, which may explain the observed phenomenon.
  • A further reply implies that the issue may stem from the experimental apparatus itself, questioning whether the setup is at fault.
  • Another participant compares perfect polarizers to idealized concepts like frictionless surfaces, indicating that perfect polarizers do not exist in practice.

Areas of Agreement / Disagreement

Participants generally agree that the inability to achieve complete darkness is due to the imperfections of the polarizers, but the discussion does not resolve whether the issue lies specifically with the experimental setup or the nature of polarizers themselves.

Contextual Notes

The discussion does not address specific limitations of the experimental setup or the definitions of terms used, leaving some assumptions and conditions unresolved.

quietrain
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Hi,

when i am doing an experiment that uses two polarizers (Cross) to achieve complete annihilation of light,

why am i not able to see complete darkness when i look at the light source from the end of the polarizers, but rather the light source changes to a different color

for example, if i have a blue light source, i see it become dark blue, but never really black.

so is there a reason? theoretically i am suppose to kill 100% of the light right?

thanks!
 
Science news on Phys.org
The polarizers are imperfect.
 
so its a fault on the experiment apparatus?
 
Yes. Perfect polarizers are in the same category as frictionless surfaces.

You might suggest to the http://www.lhup.edu/~dsimanek/ideal/ideal.htm that they add perfect polarizers to their catalog. :smile:
 
haha ok thanks!
 

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