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There are a few websites that talk about how certain creatures can produce circularly polarized light in nature (i.e., certain beetles, fireflies, mantis shrimp, etc.), but I have found very few articles explaining how circularly polarized light can occur in nature outside of the animal world (i.e., natural physical processes, the weather, water-air interfaces, etc.).


Two articles I’ve found seem to indirectly suggest that fog/clouds/dust, etc., can produce circularly polarized light:

“New circular polarizing filter may replace existing multi-layer approach to achieve the ability to see through dust and clouds.” (“Polarization Imaging: Seeing Through the Fog of War.” Robert P. White, Ph.D.)

“But a filter that could let people see — or block out — all the polarizations of visible light would do much more than just make a day at the beach more comfortable. Such a filter could also help pilots see through fog, haze or clouds of dust;” (“Camera Filter Cuts Through Fog, Camouflage.” Francie Diep. NBC News)


After reading these articles, I reached the conclusion that if they are using circular polarizing filters to see through fog, haze, clouds, or dust, it must be because, somehow, these phenomena polarize light circularly. This conclusion may have been incorrect. If correct, however, I am still unsure of the relationship between circularly polarized light and fog, clouds, haze, and dust. Do these phenomena really produce circularly polarized light, and if so, how do they do it? Are there any other natural phenomena that produce circularly polarized light?


Sources:

Articles about circular polarization in nature:

  1. Polarization [Brit] - https://www.britannica.com/science/polarization-physics
  2. Circular polarization [Wiki] - https://en.wikipedia.org/wiki/Circular_polarization#In_nature
  3. Circularly Polarized Light in Nature (Gábor Horváth. Dezső Varjú) - https://link.springer.com/chapter/10.1007/978-3-662-09387-0_15

Articles related to fog/clouds/dust and circular polarization:

  1. Polarization Imaging: Seeing Through the Fog of War (Robert P. White, Ph.D. ) - https://www.wpafb.af.mil/News/Article-Display/Article/399646/polarization-imaging-seeing-through-the-fog-of-war/

  2. Camera Filter Cuts Through Fog, Camouflage (Francie Diep. NBC News) - https://www.nbcnews.com/id/wbna46299931

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The only 2 natural phenomenon generating circularly polarised light that i know of are

  1. Optical Glory phenomenon or glory cloud: it is a ring of bright colors that appears around the shadow of an observer's head when they are facing towards the sun. The light scattered by the droplets is often circularly polarized, which is what causes the colors in the ring.
  2. Aurora borealis (northern lights) that is caused by the excitation of gas particles in the Earth's atmosphere by charged particles from the sun, which can result in the emission of circularly polarized light.

Other natural phenomenon that generate circular polarised light exist in crystals or certain molecules like calcite or mica.

Some worth-reads

One more evidence of left-handed circular polarization in comets: http://loawww.univ-lille1.fr/workshop_LOA/ELS-XIV/documents/Final_ELS.pdf

https://acp.copernicus.org/preprints/acp-2022-55/acp-2022-55-manuscript-version3.pdf

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  • $\begingroup$ What makes optical glorys more probable to produce circular polarized light? $\endgroup$
    – Mauricio
    Jan 10, 2023 at 10:59
  • $\begingroup$ @Mauricio The size/shape of the droplets and the angle at which the light strikes them. The irregular shape droplets much smaller than the wavelength of light backscatters the light towards the observer at the "glory's angle" preferentially in circular polarization. $\endgroup$
    – Haris
    Jan 10, 2023 at 11:14

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