Editing Circular polarization (section)

=== From the point of view of the receiver ===

In this alternative convention, polarization is defined from the point of view of the receiver. Using this convention, left- or right-handedness is determined by pointing one's left or right thumb {{em|toward}} the source, {{em|against}} the direction of propagation, and then matching the curling of one's fingers to the temporal rotation of the field.

When using this convention, in contrast to the other convention, the defined handedness of the wave matches the handedness of the screw type nature of the field in space. Specifically, if one freezes a right-handed wave in time, when one curls the fingers of one's right hand around the helix, the thumb will point in the direction of progression for the helix, given the sense of rotation. Note that, in the context of the nature of all screws and helices, it does not matter in which direction you point your thumb when determining its handedness.

When determining if the wave is clockwise or anti-clockwise circularly polarized, one again takes the point of view of the receiver and, while looking {{em|toward}} the source, {{em|against}} the direction of propagation, one observes the direction of the field's temporal rotation.

Just as in the other convention, right-handedness corresponds to a clockwise rotation, and left-handedness corresponds to an anti-clockwise rotation.

Many optics textbooks use this second convention.<ref name="Polarization_in_Spectral_Lines_Section_1.2">Polarization in Spectral Lines. 2004 E. Landi Degl'innocenti, M Landolfi Section 1.2 "When ... the tip of the electric field vector rotates clockwise for an observer facing the radiation source, ... (it will be considered)... positive (or righthanded) circular polarization, Our convention ... agrees with those proposed in the classical textbooks on polarized light by Shurcliff (1952) and by Clarke and Grainger (1971). The same convention is also used, although with some few exceptions, by optical astronomers working in the field of polarimetry. Many radio astronomers, on the other hand, use the opposite convention. [https://books.google.com/books?id=8sl2CkmZNWIC&dq=circular+polarization+conventions&pg=PA5]</ref><ref>HANDBOOK OPTICS Volume I, Devices, Measurements and Properties, Michael Bass Page 272 Footnote: "Right-circularly polarized light is defined as a clockwise rotation of the electric vector when the observer is looking ''against'' the direction the wave is traveling."</ref> It is also used by [[SPIE]]<ref>{{cite web|title=The Polarization Ellipse|url=https://spie.org/publications/fg05_p07-09_polarization_ellipse|website=spie.org|access-date=13 April 2018}}</ref> as well as the  [[International Union of Pure and Applied Chemistry]] (IUPAC).<ref>{{cite journal |title=Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006) |author=S. E. Braslavsky |url=https://www.degruyter.com/downloadpdf/journals/pac/79/3/article-p293.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.degruyter.com/downloadpdf/journals/pac/79/3/article-p293.pdf |archive-date=2022-10-09 |url-status=live |journal=Pure and Applied Chemistry |volume=79 |issue=3 |pages=293–465 |date=1 January 2009 |doi=10.1351/pac200779030293|s2cid=96601716 }}</ref>