Novel Detection of Optical Orbital Angular Momentum.

摘要

A light beam carry Orbital Angular Momentum (OAM) has typical wave front and singularity at the optical axis. The corresponding azimuthal phase is weighted by an integer number which fundamentally represents the OAM component along the propagation. These characteristics have great advantages to be employed in signal transmission technique. Extreme large number of the Hilbert spaces would be available; however, OAM states are sensitive for the atmospheric turbulence even in the weak regime. Paterson describes the generated scattering by the presence of the turbulence. The decoherence effect that associates with Languerre-Gauss beam is considered and the probability of obtaining different OAM measurements is also calculated. Later on, Taylor and Boyd considered optical vortex beams with constant amplitude. They determined the probability to detect a photon with no change in its OAM states among traveling inside the atmosphere. Both studies assume only a phase distortion causes by the atmospheric turbulence with no change in the wave amplitude.