Fractional rotational Doppler frequency shift for detecting spin acceleration

The detection of angular acceleration has broad applications in remote sensing, including platform attitude control, dynamic target tracking, and environmental monitoring. The rotational Doppler effect of structured light carrying orbital angular momentum has shown great potential for measuring angular velocity. However, when the angular velocity varies, a chirped intensity signal is generated, and the frequency spectrum of traditional RDE analysis broadens, which hinders the accurate extraction of velocity or acceleration information. To address this challenge, fractional rotational Doppler frequency analysis was introduced to measure angular acceleration in cases of variable velocity motion illuminated by conjugate vortex beams. Experimental results demonstrate that fractional rotational Doppler frequency analysis not only effectively handles time- varying signals from accelerating objects, but also exhibits strong resistance to environmental noise and atmospheric turbulence. These advancements hold significant potential for practical applications in fields such as aerospace, deep-sea exploration, and beyond.