Ring Pearcey vortex beam dynamics through atmospheric turbulence

The subject of free space optical communication (FSO) with an optical beam carrying orbital angular momentum (OAM) has attracted a great deal of research attention over the last two decades. Efforts to understand, model, and execute communication links through a turbulent atmosphere with OAM beams have gained particular importance. In this regard, different types of shape-preserving beams, which can withstand turbulences of varying strengths, have been proposed and studied. In this paper, we present a numerical investigation of the propagation characteristics of a ring Pearcey vortex beam (PVB) through turbulent atmosphere. The study details moderate as well as strong atmospheric turbulences. The modified von Kármán model has been relied on to model random phase screen. In moderate turbulence, the ring PVB preserved its singularity. In strong turbulence, the ring PVB preserved its singularity for short propagation distances but lost its singularity at longer propagation distances. We found that, upon increasing the value of a topological charge ( l ), the aperture averaged scintillation index (SI) increases. We calculated the aperture averaged SI for different truncation factors and noticed that the ring PVB with a truncation factor b =0.1 performed better in stronger turbulence. In moderate turbulence, the aperture averaged SI performed better for shorter propagation distances and relatively larger truncation factors. Further, we calculated the aperture averaged SI for a spatially chirped ring PVB, finding that aperture averaged SI improved largely for the negatively chirped ring PVB. Further, on comparing the aperture averaged SI of the ring PVB and ring Airy vortex beam (AVB), it has been noticed that, in strong turbulence, the ring PVB exhibited better aperture averaged SI. Additionally, we have calculated the beam wander for the ring PVB and ring AVB, finding that the ring PVB demonstrates better beam wander.