Scattering of vortex beams by typical targets and its experimental research

Vortex beams have a broad application prospect in the fields of information modulation, detection, and identification of targets because they carry orbital angular momentum. First, the related theories of vortex beam and bidirectional reflection distribution function are introduced. Differential surface element method is a numerical calculation method that discretizes the problem domain into small panels, approximates the properties of the problem, and transforms it into a system of algebraic equations. The expression for the backscattered intensity of a vortex beam illuminating a typical target (sphere, cylinder, cone, and dome) is derived by combining the scattering theory and the differential surface element method, and simulations are carried out. Finally, the theoretical analysis was verified by the experiments. The results show that: for different targets, the difference between the backscattered power curves of the vortex beam is larger, which is conducive to target identification; for the same target, the peak range of the backscattered power curve of the vortex beam is wider, which is conducive to the detection of multiple angles; when the typical target is a sphere and the material is different, the peak value of the backscattered power curve of the vortex beam changes with the change of the material but the trend of the change is basically the same.