Rotational Doppler Effect With Vortex Beams: Fundamental Mechanism and Technical Progress

Structured light beams such as optical vortices can carry the orbital angular momentum (OAM) with an unbounded quantum number. Recent years have witnessed a growing interest in rotational Doppler effect vortex light. Here we present overview on technical progress measuring associated OAM. This includes how high-order OAM beam is crucial for realizing high-sensitivity remote sensing of rotating objects. The basic physical mechanism manifested from both perspectives wave property and conservation law energy. Besides, summarize extension linear optics to nonlinear optics, realms. Also, discuss main challenges opportunities realistic scenario future applications.