In recent years the study of structured light, specifically orbital angular momentum (OAM), for remote sensing and free-space optical communications has gained great interest. Laser beams propagating through the atmosphere are susceptible to optical turbulence, which leads to beam distortions in the form of scintillation, beam wander, increased beam spreading, and loss of temporal and spatial coherence. One method that has been predicted to reduce scintillation is the use of partially coherent beams that can be propagated via their coherent mode representation (CMR). For the case of communications this is of great importance as scintillation reduction can lead to improved link effectiveness. For a spatially division multiplexed system employing OAM, reduction of the beam’s spatial coherence will possibly impede on the ability to separate the spatial modes on the output. A partially coherent beam carrying OAM through its CMR is the Im Bessel beam that recently has been experimentally realized. To expand upon the possible uses of the Im-Bessel beam, this paper intends to take a first step at simulating and quantifying the beam’s CMR through time-correlated optical turbulence. In this way, traditional beam metrics such as scintillation, beam spreading, spatial coherence, and OAM spectrum can be quantified. New degrees of freedom, such as CMR cycling rate and detector sampling rate relative to the turbulence, will also be explored.
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