Structurally stable beams in the turbulent atmosphere: dark and antidark beams on incoherent background [Invited

Abstract

We demonstrate analytically and verify numerically that recently discovered, and experimentally realized, partially coherent dark and antidark beams are structurally stable on propagation in a statistically homogeneous, isotropic random medium, such as the turbulent atmosphere. The dark/antidark beams defy diffraction in free space, and they manifest themselves as dark/bright notches/bumps against an incoherent background. The structure of a bump/notch remains invariant on propagation of the beam through the random medium, while the peak amplitude of the bump/notch decays with the propagation distance in the medium at a rate dependent on the strength of the medium turbulence. We also evaluate numerically the scintillation index of such beams and show that it is significantly lower than that of generic, low-coherence Gaussian Schell-model beams. The combination of structural stability and low scintillations makes partially coherent dark/antidark beams very promising candidates for information transfer and optical communications through atmospheric turbulence.