Simultaneous detection of rotational speed and direction of rotating vortex light under arbitrary pose conditions

Due to its unique orbital angular momentum property, vortex light induces the angular Doppler effect when interacting with rotating objects-this provides a method for detecting the rotational speed of rotating objects. Beyond rotational speed, the rotation vector of an object also includes the direction of rotation. Simultaneously detecting these two rotational elements is conducive to describing the complete motion characteristics of rotating objects and holds significant research value in fields such as motion perception and path planning. At the current stage, most of the research on rotating target detection based on vortex beams focuses on the polarization demodulation of light under collimated illumination conditions. This paper proposes a method for the simultaneous detection of the rotational speed and direction of a target based on rotating vortex light. By using a rotating vortex beam as the light source, the method achieves the accurate extraction of the target's rotational speed and the identification of its rotational direction simultaneously through frequency shift analysis under various conditions, such as collimated incidence and offset incidence. The effectiveness of this scheme is verified in experiments. This study provides a new idea for rotating vortex light detection and offers a methodological reference for the multidimensional detection of moving objects.