# Is "non-polarized" light made up of equal amounts of circularly polarized clockwise and counter-clockwise light?

Is "non-polarized" light made up of equal amounts of circularly polarized clockwise and counter-clockwise light, the way it's made up of equal amounts of horizontally and vertically polarized light?

It seems that I can make horizontally or vertically polarized light by passing it through a linear polarizer, like Land's Polaroid film. However, since a common way to make circular polarizers is to combine a linear polarizer and a quarter-wave filter, I'm curious if I can decompose all "non-polarized" light into equal amounts of light spinning in both directions, or if that question even makes sense.

A related question is whether or not light is ever naturally polarized circularly, at least here on Earth.

• Wikipedia has a couple of examples of circular polarization in nature. Jan 2, 2020 at 0:23
• Thanks for the reference! I'll update the question. Meanwhile, do you know the answer?
– vy32
Jan 2, 2020 at 1:33

Is "non-polarized" light made up of equal amounts of circularly polarized clockwise and counter-clockwise light, the way it's made up of equal amounts of horizontally and vertically polarized light?

Yes, this is precisely correct. For any pair of mutually-orthogonal polarizations (be they linear, circular, or elliptical), unpolarized light contains equal amounts of both members of the pair.

That said, though, be careful with this:

since circular polarizers are actually the combination of a linear polarizer and a quarter-wave filter

That's not the case. The LP+QWP combination is the easiest way we (humans) have available to make circular polarizers, but that doesn't mean that that's what they "are".

• Thanks. I edited my question to eliminate the error.
– vy32
Jan 2, 2020 at 3:31
• @Emilio Pisanty So if i combine horizontally polarized light and vertically polarized light, the result will be an unpolarized light, am i right?
– user248881
Jan 2, 2020 at 3:51
• @user248881 Without more specific details, no, that is not right (in general). But this is not the place. Read the relevant Wikipedia pages (at the very least, if you really do not have access to a suitable textbook), and then ask separately. Jan 2, 2020 at 4:32