Intensity as light passes through two quarter-wave plates?

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SUMMARY

The discussion focuses on the behavior of unpolarized light passing through a series of optical components: a polarizer at 0°, a quarter-wave plate at 45°, a second quarter-wave plate, and a final polarizer at 90°. The first quarter-wave plate converts linearly polarized light into circularly polarized light. The challenge lies in determining the optimal angle for the second quarter-wave plate to maximize intensity output as it passes through the final polarizer. The use of Jones calculus is recommended for analyzing the intensity output and polarization states throughout the process.

PREREQUISITES
  • Understanding of optical polarization and polarizers
  • Familiarity with quarter-wave plates and their phase-shifting properties
  • Knowledge of Jones calculus for analyzing polarization states
  • Basic principles of light intensity and transmission through optical components
NEXT STEPS
  • Study the principles of Jones calculus for optical systems
  • Research the effects of quarter-wave plates on light polarization
  • Explore the mathematical calculations for intensity output in polarized light systems
  • Investigate alternative methods for analyzing light transmission through optical components
USEFUL FOR

Optical physicists, students studying optics, engineers working with optical systems, and anyone interested in the behavior of polarized light through various optical devices.

Mulz
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I have unpolarized light passing through a polarizator assuming the angle 0°. The polarized light then passes through two quarter-wave plates, the first one with the angle of 45° (maximum intensity) and the other one. Then it passes through a last polarizator having an orientation perpendicular to the first polarizator, that is 90°.

What is the intensity output? I don't know how the polarized light behaves when reaching the quarter-wave plates. What angle should the second one be for maximum transmission?

It is in my understanding that quarter-wave plates only causes a phase shift in the electric components, 45° will cause circular polarization and anything else elliptically. Reaching the other should make it linearly polarized. I just don't understand how to calculate the output intensity. I have read that quarter-wave plates does not affect intensity but how come they can cancel each other out then.
 
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Mulz said:
I have unpolarized light passing through a polarizator assuming the angle 0°. The polarized light then passes through two quarter-wave plates, the first one with the angle of 45° (maximum intensity) and the other one. Then it passes through a last polarizator having an orientation perpendicular to the first polarizator, that is 90°.

What is the intensity output? I don't know how the polarized light behaves when reaching the quarter-wave plates. What angle should the second one be for maximum transmission?

It is in my understanding that quarter-wave plates only causes a phase shift in the electric components, 45° will cause circular polarization and anything else elliptically. Reaching the other should make it linearly polarized. I just don't understand how to calculate the output intensity. I have read that quarter-wave plates does not affect intensity but how come they can cancel each other out then.

This type of problem is easily analyzed by using Jones vectors/matrices:

https://en.wikipedia.org/wiki/Jones_calculus
 
Andy Resnick said:
This type of problem is easily analyzed by using Jones vectors/matrices:

https://en.wikipedia.org/wiki/Jones_calculus
We haven't gone through that.

Is there another way of determining the intensity as it passes through:

Polaroid (0°) → Quarter wave-plate (45°) → Quarter-wave plate (?°) → Polaroid (90°)

The second quarter-wave plate should have an angle in which intensity transmitted total intensity is at maximum. Not sure how to get it.
 
Mulz said:
We haven't gone through that.

Is there another way of determining the intensity as it passes through:

I'm sure there are other ways, using the Jones calculus is just the easiest. Do you understand what is meant by 'Quarter wave-plate (45°)': what is at 45°? Try thinking about this- what is the polarization state of the light after it passes through the first retarder?
 
Andy Resnick said:
I'm sure there are other ways, using the Jones calculus is just the easiest. Do you understand what is meant by 'Quarter wave-plate (45°)': what is at 45°? Try thinking about this- what is the polarization state of the light after it passes through the first retarder?

Through the first polaroid it become linearly polarized. I'm not sure what the angle of the quarter-wave plate does. I know that it phase shifts the electric vector components so they oscillate with a 90 degree difference, basically circular polarization. Not sure what 45 degrees does on it.
 
Anyone?
 

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