Based on the rotational Doppler effect, an orbital angular momentum beam can measure the lateral rotation velocity of an object, which has broad application prospects. However, all existing research focus on the light spot center coinciding with the rotation center, or only with small center offset. This is difficult to ensure in remote detection applications. In this paper, the rotational Doppler frequency shifts under three cases, including no center offset, small center offset and large center offset, are analyzed theoretically. Through theoretical research results, a novel method of measuring rotation velocity is proposed, with the light spot completely deviated out of the rotation center. A laboratory verification experiment shows that this proposed method breaks the limit of center offset of lateral rotation velocity measurement and is of great significance to the remote detection of non-cooperative rotation object.

中文翻译：

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轨道角动量光斑完全偏离旋转中心的转速检测

基于旋转多普勒效应，轨道角动量光束可以测量物体的横向旋转速度，具有广阔的应用前景。但是，所有现有的研究都集中在与旋转中心重合的光斑中心上，或者仅在中心偏移很小的情况下。在远程检测应用中很难确保这一点。本文对无中心偏移，小中心偏移和大中心偏移三种情况下的旋转多普勒频移进行了理论分析。通过理论研究结果，提出了一种新的测量旋转速度的方法，使光斑完全偏离旋转中心。