The Shack-Hartmann wavefront sensor measures wavefront slopes by analyzing the displacement of focal spots formed by a microlens array. Based on these slope measurements, wavefront reconstruction can be achieved by solving the difference equations that relate slope to phase. A wavefront reconstruction algorithm based on the region-growing method is proposed. Numerical simulations are conducted to compare its performance with the Southwell method for reconstructing various simulated wavefronts. The noise resistance of the algorithms was analyzed by introducing additive white Gaussian noise, and experimental results further validated the effectiveness of the proposed method. The findings indic... More >

Vortex beams carrying orbital angular momentum enable a new multiplexing dimension for optical wireless communications. However, atmospheric turbulence induces beam broadening, intensity scintillation, beam wander, angle-of-arrival fluctuations, and OAM crosstalk, degrading propagation performance. This review summarizes the fundamental theories of vortex beams and atmospheric turbulence, analyzes turbulence-induced effects, and surveys domestic and international research progress, introduces representative research achievements of the team from Xi'an University of Technology, and finally prospects the future development directions of this field. More >