Generation of structured beams with optional turbulence levels using a digital micromirror device

The dynamic spatial control of light fields, including spatial shaping and turbulence simulation, is essential for applications such as free-space optical communication. We propose a method for generating and rapidly switching structured beams with coherently superposed modes and optional turbulence levels using a digital micromirror device (DMD). The composite holograms encoded by Lee and Superpixel methods are quantitatively analyzed in terms of fidelity and efficiency, and both can generate structured beams under turbulence with high fidelity. The loaded turbulence intensity is verified by measuring the Strehl Ratio of generated beams, and the propagation characteristics is verified by reconstructing the three-dimensional spatial field through a stack of cross-sectional images. A more compact and robust experimental system is adopted, which reduces the power loss than traditional two consecutive modulations and improves the switching speed than phase-only modulators. The measurements consist with theoretical simulations, and the experimental method will promote applications of DMD in structured beam generation.