Abstract

A light beam carrying orbital angular momentum (OAM) has a spiral type of wave front that surrounds a zero intensity singularity. The azimuthal phase is characterized by an integer number which fundamentally represents the OAM component along the direction of propagation. OAM can be used for information encoding (communications) with the advantage that the modes correspond to an essentially infinite Hilbert space. However, OAM states are sensitive to atmospheric turbulence even in the weak fluctuation regime ^1,2. Paterson developed an approach for describing the effect of the turbulence on OAM. He considered the de-coherence a Languerre-Gauss beam and the probability of maintaining different OAM states when propagated through turbulence. Tyler and Boyd considered optical vortex beams with constant amplitude. They determined the probability to detect a photon with no change in its OAM states after traveling through the atmosphere. Both studies assume only a phase distortion caused by the atmospheric turbulence with no change in the wave amplitude.

© 2013 Optical Society of America