Spiral spectrum of multi-modified Bessel-Gaussian Schell beams in non-Kolmogorov turbulence

On the basis of the Rytov approximation, we investigate the effects of non-Kolmogorov turbulence on the spread of the spiral spectrum and the received power of multi-modified Bessel-Gaussian Schell (MMBGS) beams carrying orbital angular momentum. Numerical results show that the spread of the spiral spectrum increases as the azimuthal index of the source increases and that an optimal value of the beam waist is obtained. We find that the spread of partially coherent MMBGS beams with short wavelength is more robust than that of beams with long wavelength. The complete reverse is true for fully coherent MMBGS beams.