Phase-Dislocation-Mediated High-Dimensional Fractional Acoustic-Vortex Communication.

With unlimited topological modes in mathematics, the fractional orbital angular momentum (FOAM) demonstrates the potential to infinitely increase the channel capacity in acoustic-vortex (AV) communications. However, the accuracy and stability of FOAM recognition are still limited by the nonorthogonality and poor anti-interference of fractional AV beams. The popular machine learning, widely used in optics based on large datasets of images, does not work in acoustics because of the huge engineering of the 2-dimensional point-by-point measurement.

Perfect Acoustic-Vortexes Constructed by the Fourier Transform of Quasi-Bessel Beams Based on the Simplified Ring Array of Sectorial Planar Transducers.

Benefiting from the independence of the vortex radius on the topological charge (TC), the perfect acoustic-vortex (PAV) with an angular phase gradient exhibits important perspectives in acoustic applications. However, the practical implementation is still restricted by the limited accuracy and flexibility of the phase control for large-scaled source arrays. An applicable scheme of constructing PAVs by the spatial Fourier transform of quasi-Bessel AV (QB-AV) beams is developed using the simplified ring array of sectorial transducers.