Intensity correlation technique for mode detection and information encoding with structured-light superpositions

We present an intensity-only correlation methodology for mode recognition and information encoding in turbulence-limited free-space optical links utilizing Laguerre-Gaussian (LG) modes and their superpositions. While conventional single LG modes degrade rapidly with increasing turbulence strength, petal beams formed by superposing modes with opposite helicity exhibit enhanced correlation contrast, reduced crosstalk, and improved recognition accuracy. This leads to higher channel capacities, reaching the theoretical limit under weak turbulence. Furthermore, we experimentally show the feasibility of the method by implementing spatial multiplexing schemes as well as grayscale and color image transmission. These results establish intensity-correlation with structured-light superpositions as a straightforward yet effective framework for turbulence-resilient, high-capacity free-space optical communication.