Detection of Multiple Spinning Objects Based on Orbital Angular Momentum

In this paper, it presents a method for detecting multiple spinning objects utilizing orbital angular momentum (OAM). The Zoom-FFT method is applied to determine the rotational Doppler frequency shift (RDFS), with the number of spectral peaks indicating the number of spinning objects. Subsequently, the angular velocities of spinning objects can be obtained based on the RDFS. The simulation outcomes reveal that the proposed method can detect multiple spinning objects with similar angular velocities when illuminated by 1-mode OAM beams. Additionally, the maximum relative error of angular velocities is found to be less than 0.1%.