Evolutions of ring Airy vortex beam and ring Pearcey vortex beam in turbulent atmosphere and a comparative analysis of their channel efficiencies and OAM spectra

TL;DR

This study investigates the propagation behavior, channel efficiency, and OAM spectra of ring Airy vortex and ring Pearcey vortex beams in turbulent atmosphere, revealing their differences in robustness and spectral dispersion under various turbulence conditions.

Contribution

It provides a comparative analysis of RAVB and RPVB beams in turbulent atmosphere, including their channel efficiencies and OAM spectral characteristics, which was not previously explored.

Findings

RAVB outperforms RPVB in weak turbulence in terms of channel efficiency.

Channel efficiency decreases with increased mode numbers and mode gap.

RPVB spectra are more dispersive than RAVB spectra under turbulence.

Abstract

An optical vortex beam propagating through turbulent atmosphere encounters distortions in the wavefront that results in modal scattering. Abruptly autofocussing (AAF) beams with orbital angular momentum have gained significant attention due to their non-diffracting and self-healing nature. These warrants understanding of the behaviour of these beams through turbulent atmosphere absolutely necessary. With this intuition, in the present work we investigate the behaviour of two AAF beams namely ring Airy vortex beam (RAVB) and ring Pearcey vortex beam (RPVB) through the turbulent atmosphere in two cases-multiplexed and non-multiplexed. We propagate multiplexed as well as non-multiplexed RAVB and RPVB in different levels of turbulent atmosphere. In non-multiplexed case, channel efficiency declines for both the beams with increase in modes numbers. In multiplexed case, increasing the gap between the mode sets results in decrease in channel efficiency. We also report that in weak atmospheric turbulence RAVB outperform RPVB in terms of channel efficiency. We use optical transformation sorting (log-polar) method to demultiplex the optical beams at the output. Furthermore, we investigate and compare the OAM spectra of both beams in different levels of atmospheric turbulence and at different propagation distances. The comparison reveals that the spectra of RPVB are more dispersive as compared to that of RAVB.