Talk:Circular polarization

message: Citation:
Circular (and eliptical) polarization is possible because the propagating electric (and magnetic) fields can have two orthogonal components with independent amplitudes and phases (and the same frequency).
I would understand circular polarisation if E and M fields could have different frequencies. But with same frequencies, as stated here, I don't see why there should be circular polarization. Thanks, --Abdull 20:51, 4 Apr 2005 (UTC)
thread_title:  

message: Now that this has a publicly accessible manifestation, in 3D movies such as Real D, could we have something more about the practicalities, circularly polarizing materials and Liquid Crystal filters for circular polarization, or at least links to articles about them? (I was intrigued that the left and right lenses of my briefly hired 3D glasses seemed to have different effects on colour filters in the theatre, and on my cellphone display. More about that would be interesting -- Hugh7 (talk) 08:34, 24 December 2007 (UTC)
thread_title:  circularly polarizing materials 

message: About this paragraph:
The term "circular polarization" is often used erroneously to describe mixed polarity signals used mostly in FM radio (87.5 to 108.0 MHz), where a vertical and a horizontal component are propagated simultaneously by a single or a combined array. This has the effect of producing greater penetration into buildings and difficult reception areas than a signal with just one plane of polarization. 
This would be an instance where the polarization would more appropriately be called random polarization (or simply unpolarized). See Stokes parameters.
If I understand correctly, an ordinary dipole antenna will radiate a linearly polarized wave. If there is a second radiating dipole nearby (a simple "array"), polarization of the wave seen at a distance from the antenna will depend on both the relative orientation of the second dipole and the relative phase of the signals driving the two dipoles (phasing is affected by feed line length differences, among other factors). In any case, if the two signals have a relative phase other than 0 or pi, the wave will necessarily be elliptically polarized, with circular polarization as a special case if the relative phase and amplitudes are just right.  As long as the antennas do not move, I think the polarization state, for a line-of-sight signal, in any particular direction, will be stable and well defined as well and should not be called unpolarized.
--AJim (talk) 20:48, 19 March 2009 (UTC)
thread_title:  FM Radio 

message: The article needs to be more concise!  —Preceding unsigned comment added by 96.248.168.165 (talk) 22:45, 6 April 2009 (UTC)
replies: text: What do you mean by "mechanics"? Are you asking, "how do you make a filter that produces circularly polarized light"? --AJim (talk) 01:54, 20 May 2009 (UTC)
thread_title: complaints

message: In this equation
: \mathbf{E} ( \mathbf{r} , t ) = \mid \mathbf{E} \mid  \mathrm{Re} \left \{  |\psi\rangle  \exp \left [ i \left  ( kz-\omega t  \right ) \right ] \right \}  
I see the variable r on the left side, but I see z on the right in the exponent and I do not know how these two variables are related. The variable z is not defined. Please forgive my ignorance if this should be obvious. However, if I need help, perhaps there are some other readers who will too. I do understand the significance of t as time, although I think it, and r should be defined also.
: \mathbf{B} ( \mathbf{r} , t ) = \hat { \mathbf{z} } \times \mathbf{E} ( \mathbf{r} , t )   
My same question applies to the :  \hat { \mathbf{z} }  in the second equation. How is it related to r? --AJim (talk) 01:11, 13 May 2009 (UTC)
thread_title:  meaning of variable z in mathematical description section 

message: The images in the "General Description" section appear to be incorrect. Their captions should be switched. The animations of the handedness appear correct, but they are opposite of these incorrectly captioned images when you compare the helixes.  — Preceding unsigned comment added by 2601:285:8200:64F0:89A2:58FF:DB15:44C1 (talk) 21:34, 11 December 2022 (UTC)
thread_title:  Left handed verses right handed clarification Continued. 

message: I reworked the introductory sentence because of the creation of a new first section, General description. No information was lost, it was worked into the new section.
The images are the appropriate size for my computer screen resolution of 1280x800 but are 25% wider for those using a resolution of 1024x768 but it doesn't seem to be too bad. The images are also somewhat distorted using that resolution. I don't know the percentage of people using each resolution but I don't know how it could be avoided anyway. I've read the thumbnail help section but if you know of a way to overcome this issue please let me know.  Dave3457 (talk) 04:15, 14 April 2010 (UTC)
thread_title:  Creation of a new first section...,General description 

message: I removed the bracketed note about the British spelling of polarization which read “In electrodynamics, circular polarization (also circular polarisation) of electromagnetic radiation is a polarization such that ….” Instead I just included a reference. I don’t know about anyone else but I can’t help but feel the bracketed note is a major distraction for the reader in a sentence that is very important and is all ready very concentrated with more important information. It doesn’t help that the spellings are so close and an “s” looks a lot like a “z”. I know personally that when I first read it, it completely threw me off. The alternative British spelling of polarization is already noted in the first sentence of the Polarization article and I’m not sure that isn’t enough. Ruining the flow of such an important sentence seems to be a very high price to pay for such a thing and doesn’t serve the British people any more than anyone else given its distractive nature.
The ratio of Google hits between "circular polarization" and "circular polarisation" is 5:1 and so it can be argued that it should mentioned more prominently, however I don’t believe such a high price has to be paid. It could be argued that more than a footnote is in order to warn people who are using search engines to research the subject, however, again, I think the first sentence is jammed with enough information as it is. Dave3457 (talk) 04:15, 14 April 2010 (UTC)
thread_title:  British spelling of circular polarization 

message: While I added 3 animations just now, 2 are identical and so only 2 will be downloaded from the server by the surfer. Each are 290Kb and have been optimized. I tried to keep their size below 300Kb which is the size of the animation in the GIF animation article. If there are excessive delays in downloading the page, the left-handed animation can be removed if it really needs to be. Dave3457 (talk) 04:15, 14 April 2010 (UTC)
thread_title:  Added animations in Handedness section 

message: The formula for \psi_L and \psi_R were clearly wrong as they were completely independent of the relative phase between the x and y components. All that was shown was a global phase \exp \left ( \alpha_x \right ) which can be ignored as it is present in both.
If you compute \langle L | \Psi \rangle  and \langle R | \Psi \rangle  you get the correct expressions.  —Preceding unsigned comment added by 155.198.206.131 (talk) 11:06, 23 April 2010 (UTC)
thread_title:  Corrected <math>\psi_L</math> and <math>\psi_R</math> Definitions 

message: It seems that section Circular_polarization#Mathematical_description is using bra-ket notation -- anyone against simplifying it using undergraduate-level vectors and matrices notation? Thanks. Fgnievinski (talk) 03:13, 1 June 2010 (UTC)
replies: text: That would seem very appropriate. If you do change it, may I suggest that you might think about placing what is already there into a separate, possibly hidden, section titled “Mathematical Description using Bra-ket notation” or something like that. Someone obviously spent quite a bit of time putting it together and it may be of use to those familiar with the notation. Note that in quantum mechanics circular polarization is mathematically interpreted as the spin of the photon. That’s most certainly the reason for the Bra-ket notation. In fact it would be great if someone included something to that effect on this page. Everything I know about it is pretty much summed up in this quote….I’ve cut and pasted the quote here for myself, yours or anyone else’s reference. Introduction_to_Quantum_Theory_2ED_David_Park_Sec_2.2_Pg32 Dave3457 (talk) 21:35, 30 June 2010 (UTC)
replies: text: I understand where you guys are coming from, especially in the sense of actual application of the physics to real life "macroscopic" electronics (eg building antennas, measuring power delivered through EMI to a circuit, etc.).  However, understanding the physics from a purely theoeretical and "self-consistent" point of view.... where all you care about is the way to create a circularly polarized photon and not its interaction with a conductive boundary or chiral polarizer.... is easier with Bra-Ket/Dirac.  This is one of the great things about this notation:  its graphically/notationally simple.  its symmetry and lack of messy notation and symbols helps to keep your mind focused.  You don't need to worry about whether or not you must perform a convolution over a complex domain, or a messy integral equation.  Instead, you implicitly assume things about inner products, actions of operators, changes of basis, outer products, etc. that do not require as much thought.  I always appreciate straightforward R3 representations when I need to imagine something that is interacting with a real system.  But if I am concerning myself with a hypothetical particle, atom, photon, molecule, etc. that is floating in space somewhere, Dirac Notation is the way to go.184.189.220.114 (talk) 20:03, 8 March 2013 (UTC)
thread_title:  [[Bra-ket notation]] unnecessary? 

message: I noticed you’ve been putting time into the page. I’ve liked most of your changes. Some months ago I created the “General description” article/images and also tried, like you, to make the Handedness section more comprehensible. At first, for aesthetic purposes, I liked your idea of putting the left-handed images on the left side of page. I’m assuming you did it because edit links where bunching up on your screen or something. However, whatever we do I feel both images need to be on the same side of the page. That way people can more easily compare the left-handed polarization images to the right-handed polarization images. In my view practicality has to override aesthetics in this case.
Unless you object I’m going to move your quotes of the IEEE convention into the appropriate reference at the bottom of the page.  I do not see the need to put the reader through the trouble of deciphering those sentences as they do not convey any new information and can only serve to confuse the reader. What is your take? Dave3457 (talk) 21:43, 30 June 2010 (UTC)
replies: text: Hi Dave. Sorry, didn't see your msg before. Thanks for asking, but I guess the best way to catch one's attention is to edit it -- I'm all for Wikipedia:BOLD,_revert,_discuss_cycle! ;-) Thanks for your time. Fgnievinski (talk) 16:12, 2 July 2010 (UTC)
replies: text:  Ok, thanks for the link. I guess your a more aggressive personality then myself :) I do agree I could afford to be more bold, but the BRD page itself does say it should be a fall back. Dave3457 (talk) 18:08, 2 July 2010 (UTC)
thread_title:  Fgnievinski’s Recent Changes 

message: Fgnievinski, I noticed you reduced the pixel width from 485px to 400px. For people with a screen resolution of 1024X768 , 400px or even lower would be the ideal size. However this webpage, http://www.w3schools.com/browsers/browsers_display.asp  says that  76% of people use a larger screen resolution than 1024X768.(And it's rising rapidly,2009-57%_2010-76%) I personally have a resolution of 1600x900 and when viewing the page using IE, the images are definitely on the small side (Although I admit, not so small you can’t extract the information.) (Note: In IE increasing the text size does not increase the image size while in Firefox the default is to have the image size increase along with an increase in text size and so the issue is not as great for Firefox users. I think about 25% of people use Firefox. I went ahead and split the difference and set the resolution to 440px, although I am all ears if you think it is too large. I have to admit to having a bias here. Having put all of those hours into them I personally would prefer them on the large size rather than on the small size. What led you to decrease the pixel size? Note that I am not necessarily objecting but only trying to find the optimum pixel size.Dave3457 (talk) 21:53, 30 June 2010 (UTC)
replies: text: Same as above. Fgnievinski (talk) 16:15, 2 July 2010 (UTC)
thread_title:  Size of images in General Description section. 

message: For now I have removed the reference to the Federal Standard as Steve Quinn has pointed out a second reference to circular polarization handedness on their site that contradicts the present one we are referencing. (I've placed it below) I have sent an email to the Federal Standards website and am waiting for a reply. If you are interested in this issue, the email I sent is posted at Talk:Polarizer/Lengthy_quotes#Email_to_Federal_Standards_website  where Steve and I are discussing matters. 
This convention matches that of the U.S., Federal Standard 1037C.Federal Standard 1037C Circular Polarization http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm ”Circular polarization may be referred to as "right-hand" or "left-hand," depending on whether the helix describes the thread of a right-hand or left-hand screw, respectively. “
Dave3457 (talk) 00:19, 2 July 2010 (UTC)
thread_title:  Temporary removal of Federal Standards reference. 

message: It was drawn to our attention that in the Feynman's lectures, Feynman says that quantum physicists use the “From source” IEEE convention and so I included that information. (Search “Hello everyone!” on this page for the comment.) 
I also took the opportunity to do a slight rewrite of the entire section.  
Because the IEEE convention seems to be the more dominant convention I reversed the order that the two conventions were presented.
I changed the headings of the two conventions identifying them by point of view instead of user. The first convention section is now called  “First convention: From the point of view of the source”.
I created a third section summarizing who uses which convention and added a comment about how the The Institute for Telecommunication Sciences (ITS) is presently proposing two contradictory conventions of handedness. (I sent them an email several months ago with no response, after trying again I will be sending another to a different email address. Update: They are not updating 1037C any more, it is for archival purposes only. Refer here for email and response. )
I made no substantial changes with regards to who uses which convention except the addition mentioned above and the referenced comment that “Many radio astronomers ...use (the from source) convention.” 
I removed the image of the satellite, not being sure what it contributed, here is the code if someone wishes to put it back.     
With regards to its caption, note that the helix is right-handed irrespective of which direction you point your thumb, making the “as seen from the transmitter.” statement misleading.  Dave3457 (talk) 16:19, 19 January 2011 (UTC)
thread_title:  Slight rewrite of Handedness convention section 

message: The definition 
:   |\psi\rangle  \ \stackrel{\mathrm{def}}{=}\  \begin{pmatrix} \psi_x  \\ \psi_y   \end{pmatrix} =   \begin{pmatrix} \cos\theta \exp \left ( i \alpha_x \right )   \\ \sin\theta \exp \left ( i \alpha_y \right )   \end{pmatrix}   
appears to define the Bra-ket terms as 2 element vectors, which forces E to be a two element vector.  Later this vector appears in a cross product expression which is only defined for 3 element vectors.  You should explain that the direction of propagation is along the z axis and make these definitions 3 vectors with 0 z components.  However I see no reason to use this notation at all.  No one who hasn't had quantum mechanics will understand this.
While it is true that the Jones calculus is defined on a 2-D subspace, a more consistent way to view that is that a 2 x 1 Jones vector really multiplies , on the right hand side, a 3 x 2 matrix whose columns span the transverse plane, orthogonal to the direction of propagation. Perhaps even better would be to explicitly include  e_x,  e_y  unit vectors in the definition.  Oh by the way the fact that the plane wave is propagating in the z direction has to be inferred and is not explicitly stated.
If you are going to use unusual math conventions I'd almost rather see quaternions  employed here since it makes the notation considerably more compact.  — Preceding unsigned comment added by Mattcbro (talk • contribs) 02:37, 17 August 2011 (UTC)
replies: text: When is the cross product applied? It may be true that most people are not familiar with bra-ket notation, but it is also the case that most people are not familiar with quaternions, and the fact is that bra-ket notation is very suitable in this case since light polarization is quantized by nature. Can you show us how to use quaternions in this case and why it would be better? —Kri (talk) 18:24, 21 August 2011 (UTC)

text: Okay, I saw where the cross product was applied: in the beginning of the section Mathematical description. —Kri (talk) 18:37, 21 August 2011 (UTC)
thread_title:  Bra-ket notation confusing and possibly wrong 

message: Why is this separated from Polarization (waves) ? --TiagoTiago (talk) 23:21, 29 October 2011 (UTC)
replies: text: For what it is worth, Elliptical polarization and linear polarization also have their own pages. Dave3457 (talk) 03:14, 30 October 2011 (UTC)
thread_title:  Does this needs to be a separated article? 

message: I removed the following paragraph for a couple of reasons. First, I don’t think it was in the interest of the readers for the article to suddenly start talking in terms of quantum mechanics. Second, I'm pretty sure statements made in it were not true.  First, the Heisenberg uncertainty principle does not allow you to imagine traveling particles with a distinct position and momentum. Also, photons can’t stop spinning. Whoever put it their, may I suggest you correct it and put it in the quantum mechanics section in this article. Dave3457 (talk) 04:49, 22 November 2013 (UTC)
thread_title:  Paragraph from polarizer page belongs here if anywhere 

message: Really, an edit war. About the Circular polarization article. I think there are two important points alluded to here, first that the orthogonal Cartesian components do not need to be "horizontal" and "vertical". S and P polarizations are very useful, for instance. Second, that any polarization state can be described as the sum of a right and a left handed circular component. Maybe there is a better way to say it. I do think this is a good place to point it out, and not irrelevant. --AJim (talk) 03:33, 14 November 2014 (UTC)
replies: text: S and P are the same as horizontal and vertical, so the first point is moot. As for the second point, it might belong in Polarization (waves), not here -- in fact, it's already mentioned at the end of Polarization state; in circular polarization, a particular orthogonal basis has already been chosen. Fgnievinski (talk) 12:25, 14 November 2014 (UTC)
thread_title:  Other Orthogonal Decompositions 

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message: Reassess to C-class. The article fails the B-class criteria (#1 and #4). There are March 2011 and June 2021 "citation needed" tags and an April 2018 "overly lengthy quotations" tag. There are unsourced sentences, paragraphs, subsections, and sections.  --  Otr500 (talk) 17:27, 27 February 2023 (UTC)
thread_title: Article issues and classification