光束轨道角动量谱的测量技术研究进展(特邀)

Advances on the measurement of orbital angular momentum spectra for laser beams(Invited)

自Allen等证明具有螺旋相位波面的激光束携带有轨道角动量以来,对光束轨道角动量调控技术的研究取得了跨越式的发展,获得了包括相位涡旋光束、矢量涡旋光束、激光束阵列等多种新型结构光场,在超大容量光通信、遥感探测、激光加工、高分辨率成像等领域展现出广阔的应用前景。准确测量光束的轨道角动量是其应用的重要基础,早期人们更多地关注对待测光束所包含的轨道角动量成分分布的测量,后来逐步拓展至对各个轨道角动量成分的强度比重即轨道角动量谱的测量。文中系统地回顾并总结近年来光束轨道角动量谱测量技术的发展,主要介绍了包括基于衍射、模式分束等方法的新型光束轨道角动量谱测量技术。

Since Allen et al. have shown that laser beams with helical wavefront carry orbital angular momentums(OAMs), great advances have been achieved for manipulating beams’ OAMs, and contribute to lots of novel structured beams as optical phase and polarization vortices, laser beam lattices. Such structured fields can find applications in lots of domains including large-capacity data-transmission, remote detection, laser manufacture, high-resolution imaging. One of the important bases of above scenarios is diagnose the OAM spectrum. In the early stage, researchers concentrate more on the measurement of OAM distributions, and afterwards expanded gradually to the intensity proportion measurement of each OAM component, namely the orbital angular momentum spectrum. In this paper, the recent advances of OAM spectrum measurement for laser beams were systematically reviewed and summarized, covering approaches of OAM spectrum measurement based on diffraction, mode sorting and other novel methods.