Physicists Still Can't Cleanly Split Light's Spin From Its Orbital Angular Momentum
Orbital Angular Momentum of Light
Orbital angular momentum (OAM) is the part of a light beam's angular momentum tied to its spatial field distribution rather than polarization. Beams with helical wavefronts carry it, with an optical vortex at the center and an integer topological charge m. But decomposing light's total angular momentum into spin and orbital parts has been a longstanding controversy: unlike massive particles, massless photons admit no consistent split, and a topological singularity blocks the zero-mass limit.
The decomposition of total angular momentum into spin and orbital parts for massless bosons—such as photons and gluons—has been a longstanding controversy in both classical and quantum field theory.
- jdc-pub
> Research into OAM has suggested that light waves could carry hitherto unprecedented quantities of data through optical fibres. According to preliminary tests, data streams travelling along a beam of light split into 8 different circular polarities have demonstrated the capacity to transfer up to 2.5 terabits of data (equivalent to 66 DVDs or 320 gigabytes) per second.[40]
> [40] https://www.bbc.co.uk/news/science-environment-18551284
Fun!
- Kiboneu
Man, we've come a long way since "An Evolved Circuit, Intrinsic in Silicon, Entwined with Physics" (1997)
- u1hcw9nx
See also:
Spin angular momentum of light (SAM).
https://en.wikipedia.org/wiki/Spin_angular_momentum_of_light
Angular momentum of light (with nice video)