Spiral spectrum of Laguerre-Gaussian beams in slant non-Kolmogorov atmospheric turbulence

The beam carrying information will be affected by atmospheric turbulence as it propagates through the atmosphere. Under the modified Rytov method, using the non-Kolmogorov power spectrum, applying the atmospheric turbulent inner scale and the outer scale which changes with altitude, this paper obtained the expression of the spiral spectrum of the beam in slant atmospheric turbulence. The influences of wavelength, topological charge, zenith, waist radius, receiver aperture, radial index and inner scale on spiral spectrum are investigated. Numerical results reveal that spiral spectrum spread becomes more serious with longer distance, larger topological charge, larger zenith, smaller wavelength, larger receiver aperture and smaller inner scale. Radial index and waist radius have little effect on the spiral spectrum. In addition, the influence of the outer scale on the spiral spectrum under different fluctuation conditions is analyzed, the results show that if the outer scale is set as constant during the calculation of the spiral spectrum of the beam in the slant path, it will have little effect in the weak fluctuation area, but will bring large errors in the medium and strong fluctuation area.