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PavanKumar
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I understand how polarization can be explained using EM waves. However, I am unable to understand how to explain how polarization filters work when we use the concept of photon spins. Can someone help me with that?
Geofleur said:Does that mean, instead of saying that the photon has spin 1, we should instead say that it has helicity 1? I didn't realize that the representations of the Poincare group for massless particles cannot be labeled by spin!
The usual terminology is to say that the photon has spin 1 (in the sense of ##\vec{J}^2## has the lowest eigenvalue ##1 \cdot (1+1)=2##). Since the photon is massless this implies that there are two spin-degrees in freedom. A natural choice for a single-photon basis is to take momentum eigenvectors and eigenvectors of the angular momentum component in direction of the photon's mopmentum, i.e., the helicity, and this helicity ##h \in \{-1,1\}##.Geofleur said:Does that mean, instead of saying that the photon has spin 1, we should instead say that it has helicity 1? I didn't realize that the representations of the Poincare group for massless particles cannot be labeled by spin!
A photon spin refers to the intrinsic angular momentum of a photon, which is a type of elementary particle that makes up light. It is a fundamental property of photons and is always either +1 or -1, indicating the direction of its spin.
Polarization is a property of light that describes the direction of the electric field oscillations of a photon. It can be either linear, circular, or elliptical, depending on the orientation of the electric field relative to the direction of propagation.
Polarization filters, also known as polarizers, work by selectively blocking certain orientations of polarized light. They consist of a material with aligned molecules that act as a barrier to light waves with certain polarizations, allowing only those with the desired polarization to pass through.
Polarization filters are commonly used in various applications, such as photography, 3D glasses, and LCD screens. They can help to reduce glare and improve contrast, as well as manipulate the polarization of light for specific purposes, such as in optical communications.
Yes, photon spin and polarization can be changed or manipulated through various methods, such as passing light through polarizing filters, using certain materials that can change the polarization of light, or applying external forces to alter the spin of photons. These techniques are important in many fields, including quantum computing and telecommunications.