Mitigation of atmospheric turbulence with random light carrying OAM

Abstract

The results of the laboratory experiments are presented for synthesis of the Im-Bessel correlated beams by a Spatial Light Modulator (SLM) and a Digital Micromirror Device (DMD) as well as for their interactions with atmospheric turbulence simulated by either an SLM or a mixed-air turbulent chamber. The synthesis procedure of these beams relies on the incoherent superposition of their coherent modes being Laguerre-Gaussian (LG) functions having a variable radial mode and a fixed azimuthal mode carrying the Orbital Angular Momentum (OAM). As a result of such construction the correlation functions of these random beams have separable phase carrying the OAM with the index inherited from the coherent modes. The coherence states of these beams are controlled by the distribution of weights of the coherent modes in superposition, varying from perfectly coherent to nearly incoherent. We explore the effects of the cycling rates of the SLM and the DMD used for source synthesis on the average intensity and the scintillation index of the generated beams having different OAM indices and coherence states after propagation in atmospheric turbulence. Our analysis indicates that for fairly incoherent beams with sufficiently large OAM index and high cycling rates the atmospheric turbulence can be efficiently mitigated.