Spatial eigenmodes of light in atmospheric turbulence

We carry out a numerical analysis of the spatial structure of the eigenmodes of light in atmospheric turbulence and assess the distribution of the singular values under variable turbulence conditions characterized by the Fried parameter and Rytov variance. Under weak scintillation, the highly transmitting eigenmodes found here possess a modal structure that is reminiscent of Laguerre-Gaussian (LG) modes and their simple superpositions. When scintillation becomes significant, we establish that the optimal eigenmodes for communication differ substantially from LG modes and tend to have highly localized transverse intensity distributions.