Optical rotation and linear basis set

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Discussion Overview

The discussion revolves around the behavior of polarized light as it passes through optical elements, specifically focusing on the effects of a quarter-wave plate and an optical rotary crystal. Participants explore the relationship between linear and circular polarization, the rotation of basis sets, and the mathematical representation of these phenomena using Jones matrices.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions whether the orientation of the linear basis set can be rotated by the optical rotary crystal or if it remains fixed, suggesting that the basis set orientation is likely fixed.
  • Another participant argues that there is no reason for the basis set orientation to be fixed and proposes that the optical rotary crystal can indeed rotate the linear basis set, indicating a willingness to verify this through Jones algebra.
  • A participant elaborates on the interaction of linear and circular basis sets with the optical rotary crystal, stating that the results would differ based on the basis set used, particularly noting the implications of the right and left indices of refraction.
  • Several participants discuss the Jones matrices for both linear and circular rotators, providing specific mathematical forms for these matrices and their parameters.
  • There is a request for clarification regarding the distinction between linear and circular rotators, indicating some confusion about terminology used in the discussion.

Areas of Agreement / Disagreement

Participants express differing views on whether the orientation of the linear basis set is fixed or can be rotated by the optical rotary crystal. The discussion remains unresolved, with multiple competing perspectives on the behavior of polarized light in this context.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the behavior of light in different polarization states and the specific conditions under which the optical rotary crystal operates. The mathematical representations provided may depend on specific definitions and contexts that are not fully explored.

galvin452
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If I have a 45 degree linear polarized light which I then circularly polarize using a 1/4 wave plate and put this through an optical rotary crystal and then using the equivalent 1/4 wave plate but in the reverse oriention, will I get back a 45 degree linear polarized light?

Put another way, as circular polarized light can use a linear basis set 90 degrees out of phase, can the angle of the linear basis set with respect to the 1/4 wave plate orientation be rotated by the optical rotary crystal (while the phase remains circular) or is the basis set orientation always fixed?

I would think the basis set orientation is fixed but just want to make sure.
 
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There is no reason why the basis set orientation ought to be fixed. By my understanding the optical rotary crystal can rotate the linear basis set. I'd go through the Jones algebra to be sure though.

Claude.
 
Claude Bile said:
There is no reason why the basis set orientation ought to be fixed. By my understanding the optical rotary crystal can rotate the linear basis set. I'd go through the Jones algebra to be sure though.
Claude.

For a linear basis set, one can take each individual linear orientation basis as two oppositely rotating basis set so that each orthogonal linear basis is rotated by the difference between the right and left index of refraction. This would rotate the basis set as you indicated. The amount of rotation dependent on the difference between the left and right rotary index of refraction.

However if one uses a circular basis set the light is totally right circularly (or left circularly depending on the 1/4 wave plate fast slow axis orientation) polarized when entering the optical rotary crystal. Let's assume right circularly polarized, so at best it could only interact with the right index of refraction having no left component. So the right circular polarized light's reorientation would only be the result of the right rotary index of refraction.

That is to say we would get two different results depending on the basis set used.

Where is the mistake?
 
Claude Bile said:
. I'd go through the Jones algebra to be sure though.
Claude.

I can't find the Jones matix is for an optical rotary crystal? Do you know it?
 
For a linear rotator (say, sugar water), the Jones matrices are: [[cos(δ/2)+icos(2θ)sin(δ/2) isin(2θ)sin(δ/2)], [isin(2θ)sin(δ/2) cos(δ/2)-icos(2θ)sin(δ/2)]] for cartesian basis states and [[cos(δ/2) i*exp(i2θ)sin(δ/2)], [i*exp(-i2θ)sin(δ/2) cos(δ/2)]] for circular basis states, where θ is the azimuthal angle of the fast axis and δ the phase retardation.

For a circular rotator (say, the cholesteric liquid crystal phase), the cartesian Jones matrix is [[cos(δ/2) +/-sin(δ/2)], [-/+sin(δ/2) cos(δ/2)]] and for circular basis states [[exp(-/+ iδ/2) 0],[0 exp(-/+iδ/2)]].
 
Andy Resnick said:
For a linear rotator (say, sugar water), the Jones matrices are: [[cos(δ/2)+icos(2θ)sin(δ/2) isin(2θ)sin(δ/2)], [isin(2θ)sin(δ/2) cos(δ/2)-icos(2θ)sin(δ/2)]] for cartesian basis states and [[cos(δ/2) i*exp(i2θ)sin(δ/2)], [i*exp(-i2θ)sin(δ/2) cos(δ/2)]] for circular basis states, where θ is the azimuthal angle of the fast axis and δ the phase retardation.

For a circular rotator (say, the cholesteric liquid crystal phase), the cartesian Jones matrix is [[cos(δ/2) +/-sin(δ/2)], [-/+sin(δ/2) cos(δ/2)]] and for circular basis states [[exp(-/+ iδ/2) 0],[0 exp(-/+iδ/2)]].

Hi Andy, not sure whar you mean by a linear rotator vs a circular rotator. I know you can rotate the angle of linear polarized light which I assume is what you mean by a linear rotator. What is a circular rotator?
 

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