What Happens When Interfering Polarized Light Waves in X and Y Directions?

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Discussion Overview

The discussion revolves around the interference of two light waves that are polarized in orthogonal directions (x and y). Participants explore how this polarization affects the resulting interference pattern, particularly in the context of experiments like the double slit experiment. The scope includes theoretical considerations and conceptual clarifications regarding wave superposition and polarization effects.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that two light waves polarized in orthogonal directions do not interfere in intensity, suggesting that the subsequent polarization may be affected if the waves are coherent.
  • Others argue that if the path length of the two beams is the same, the result will be a wave polarized at 45 degrees to the original polarizations, with the intensity remaining the same as the original beam.
  • One participant expresses confusion about the implications of shifting the polarization by 90 degrees and questions whether this would reduce the interference pattern.
  • Another participant suggests that in the context of the double slit experiment, orthogonal polarization would lead to no interference pattern, as the waves cannot superpose to form a zero intensity, only combining independently.
  • Some participants reiterate the point that the intensity of the pattern would simply be the sum of the intensities of both waves, indicating no interference occurs.

Areas of Agreement / Disagreement

Participants express differing views on whether an interference pattern exists when light waves are polarized orthogonally. While some assert that there will be no interference pattern, others provide explanations that suggest a different outcome, indicating that the discussion remains unresolved.

Contextual Notes

Participants reference concepts such as coherence, superposition of waves, and the behavior of orthogonal vectors, but there are unresolved assumptions regarding the conditions under which these principles apply.

babblingsia
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What happens if two waves polarised in the x and y direction , say, interfere? Will the interference pattern be of less intensity? Or will there be a sharper pattern?
 
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Two light waves, polarized in orthogonal directions, do not interfere in intensity.
The subsequent polarization MAY be affected, if the two waves were prepared coherently.
 
I don't understand, taking a polarized coherent light beem spiliting it into two, shifting the polarization of one by 90 degrees. Will the interference pattern be reduced?
What do you mean by subsequent polarization MAY be affected?
 
I the case you describe, if the path length of the two beams is the same, the result will be a wave polarized at 45 degrees to each original polarilzation.
The intensity will be the same as the original beam.
 
I guess I did not frame my question clearly.What I meant is this: Consider the double slit experiment, where in you get an interference pattern on the screen. Suppose the two beams from the slits were polarised in orthogonal direction, in what way would it change the interference pattern? Would you get a sharper image?
 
Did you get this question from JEST? Just curious, since it came in JEST this year. And you live in India ;).

Well, I myself think there would be no interference pattern. Remember how interference occurs... superposition of waves. If waves in orthogonal directions cannot superpose to form a zero of intensity, they won't "interfere" as such, they'll only combine. Like a vector along x-axis can subtract a vector along the same axis, but two vectors along x- and y- axes can only act independently, and never "subtract".

One more way of seeing this is to know that the waves don't interfere if the intensity of the pattern is the sum of the intensities of both the waves (Feynman, the first chapter on QM). E2 = E12 + E22

That's precisely how orthogonal vectors add.

I myself gave the answer as "no interference pattern". :)
 
babblingsia said:
I guess I did not frame my question clearly.What I meant is this: Consider the double slit experiment, where in you get an interference pattern on the screen. Suppose the two beams from the slits were polarised in orthogonal direction, in what way would it change the interference pattern? Would you get a sharper image?
Didn't my post #2 say there would be no interference pattern?
 
pam said:
Didn't my post #2 say there would be no interference pattern?

I just tried to explain it more elaborately. :)
 

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