Accurate recognition of light beams carrying orbital angular momentum through scattering media using ghost diffraction

We report a ghost diffraction-based approach to realize accurate recognition of light beams carrying orbital angular momentum (OAM) through dynamic and complex scattering media. A bit sequence is first encoded into an OAM beam, which is sequentially modulated by a series of Hadamard patterns, and then an optical wave propagates through dynamic and complex scattering media. The collected single-pixel light intensities are temporally corrected, and ghost images can be reconstructed by using the principle of ghost diffraction. The reconstructed ghost images are further processed by using block-matching and 3D filtering with image registration, which are then utilized for OAM recognition assisted by the featured normalized cross correlation. Optical experiments are conducted to demonstrate that light beams carrying OAM can be accurately recognized in dynamic and complex scattering environments, and the proposed approach is feasible and effective. The developed ghost diffraction-based approach could open an avenue for various OAM-encoded applications in dynamic and complex scattering environments.