Jones vectors for circular polarization

In summary, according to the author, the Jones vector for right circular polarization corresponds to *left* circular polarization, and applying this vector to an arbitrary electric field results in left circular polarization.
  • #1
Decimal
75
7
Hello, I can't seem to arrive at a result that my book states using Jones vectors for circular polarization. My book says that the unit jones vector for right circular polarization is $$ \begin{bmatrix} 1 \\ -i \end{bmatrix} $$ However when I apply this jones vector to an arbitrary electric field I arrive at left circular polarization. Here is what I did: $$ \tilde E = E_0 * \begin{bmatrix} 1 \\ -i \end{bmatrix} * e^{i(k x-\omega t)}$$ $$ \tilde E = E_0 * \begin{bmatrix} 1 \\ e^{- \frac {\pi} {2} i } \end{bmatrix} * e^{i(k x-\omega t)} $$ Applying the phase shift and rewriting: $$ \tilde E = E_0 * \begin{bmatrix} cos(kx-\omega t) \\ sin(kx-\omega t) \end{bmatrix} $$ Isn't this left circular polarized light? Where did I go wrong?
 
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  • #2
Decimal said:
Hello, I can't seem to arrive at a results that my book states using Jones vectors for circular polarization. My book says that the unit jones vector for right circular polarization is $$ \begin{bmatrix} 1 \\ -i \end{bmatrix} $$

According to Azzam and Bashara [https://www.amazon.com/dp/0444870164/?tag=pfamazon01-20], your Jones vector corresponds to *left* circular polarization. (there's also a prefactor 1/√2 missing). Left-circular *lags*, because lefties are lazy laggards :)
 
  • #3
Ah yes I forgot the factor. Nevertheless both my book, my lecture notes and wikipedia all state this jones vector corresponds to right circular polarization. They even state this in old exam questions. Are you sure its supposed to be left circular?
 
  • #4
Decimal said:
Ah yes I forgot the factor. Nevertheless both my book, my lecture notes and wikipedia all state this jones vector corresponds to right circular polarization. They even state this in old exam questions. Are you sure its supposed to be left circular?

I guess at some point it's all relative. I think the definition corresponds to the direction of electric field rotation when you are facing the incoming plane wave, but the way I handle issues like this in class is to simply be internally consistent. So in your case, the incoming wave could be (I think) e^-i (kx-wt) rather than e^i(kx-wt) and then you are consistent... try that and see what you get.
 
  • #5
Thanks for the help Andy, but I think I figured out where I went wrong. I didn't realize the polarization will of course rotate in the time ##t##. The time term in the cosine and sine is however negative, which actually inverts the sine. That's why I mixed up left and right. The polarization I arrived at in my original post was actually right circular, I just didn't realize it.
 

1. What is the Jones vector representation for circular polarization?

The Jones vector representation for circular polarization is a mathematical tool used in optics to describe the polarization state of a light wave. It is a 2x1 column vector that contains two complex numbers representing the amplitudes of the electric field components in the x and y directions.

2. How is the Jones vector for circular polarization obtained?

The Jones vector for circular polarization is obtained by decomposing the circularly polarized light into its two orthogonal linear components and then expressing their amplitudes as complex numbers. The resulting Jones vector is then normalized to have a magnitude of 1.

3. What is the significance of circular polarization in optics?

Circular polarization is a type of polarized light in which the electric field vector rotates in a circular motion. It is important in optics because it can be used to control the direction and intensity of light, and it is also common in natural phenomena such as the polarization of light in the Earth's atmosphere.

4. How is the handedness of circular polarization determined using Jones vectors?

The handedness of circular polarization can be determined using Jones vectors by examining the phase difference between the two complex components of the vector. If the phase difference is positive, the polarization is right-handed, and if it is negative, the polarization is left-handed.

5. Can Jones vectors be used to represent other types of polarization?

Yes, Jones vectors can be used to represent other types of polarization, such as linear and elliptical polarization. In these cases, the Jones vector will have different complex numbers representing the amplitudes of the electric field components in the x and y directions, but the same principles of decomposition and normalization still apply.

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