# Single Photon Polarization

1. Jun 22, 2009

### psycherevolt

I was wondering how exactly a single photon is polarized. In the case of an electromagnetic wave in theoretical free space Maxwell's equations state that electric and magnetic fields must be equal in amplitude and in phase with each other. On wikipedia's "photon polarization" article it states that single photons are completely polarized. Does this mean that the polarization of single photons oscillate around a complex plane changing the linear polarization between 180 degree states perpendicular to the path of travel?

Also, in (non-theoretical) free space the index of refraction is very very close to 1, does any deviance allow for circular or elliptical polarization?

Thanks

2. Jun 22, 2009

### Bob S

Light waves from most sources are unpolarized. Light photons from most sources are unpolarized, meaning that although each photon is polarized (meaning its electric vector is along a certain direction), the assemblage of photons have a random transverse orientation. Exceptions are:blue sky light at 90 degrees to the sun on a very clear day, Brewster's angle reflected light from a lake, glossy painted surface etc.

The ratio of E to H in the MKS system (volts per meter, amp-turns per meter) is 377 ohms in vacuum. E and H are orthogonal to each other and to the direction of propagation.

3. Jun 22, 2009

### psycherevolt

You didn't answer my question. I'm asking if the linear polarization state of a single photon oscillates 180 degrees due to the coupling of electromagnetic waves in free space. Say you had linearly polarized light on the y-axis propagting on the z-axis. Does a single photon oscillate so that its polarization varies between + and - y directions?

4. Jun 22, 2009

### Bob S

See sections 1.2.2 and 4.1.3.2 on circular polarization of single photons
http://wapedia.mobi/en/Photon_polarization [Broken]

Last edited by a moderator: May 4, 2017