Effects of atmospheric turbulence on the mode weight of the Laguerre-Gaussian Schell beams

Based on the Rytov approximation, we analyze the effects of the turbulence on the crosstalk and spatial spread of orbital angular momentum modes of the Laguerre-Gaussian Schell (LGS) beams. Our results show that the spatial incoherence of light source increases the crosstalk effect of atmospheric turbulence among the orbital angular momentum states and the spatial spread of modes. The mode weight decays with the mode quality factor increasing and the refractive index structure parameter increasing. The quality factor of LGS modes increases with the increasing of refractive index structure parameter in approximate linear form.