Measuring the topological charge(TC) of optical vortices is of great importance in applications of vortex beams. A flexible and convenient method to determine the TC of an optical vortex is proposed by using an elliptical airy phase mask (EAPM). The mask can be embedded into a typical vortex generation setup, in which no additional optical elements are required. The number and the sign of TC are respectively obtained by analyzing the number and the direction of dark stripes in the far-field diffraction patterns of the vortex beam companied with EAPM. It is experimentally demonstrated that this method is able to measure TCs of both conventional and perfect vortex up to ±120.

中文翻译：

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使用椭圆艾里相位掩模测量光学涡旋的拓扑电荷


测量光学涡旋的拓扑电荷（TC）在涡旋光束的应用中具有重要意义。提出了一种利用椭圆艾里相位掩模（EAPM）确定光学涡旋TC的灵活便捷的方法。该掩模可以嵌入到典型的涡流发生装置中，其中不需要额外的光学元件。通过EAPM分析涡旋光束远场衍射图中暗条纹的数量和方向，分别得到TC的数量和符号。实验证明，该方法能够测量常规涡旋和完美涡旋的TC，最高可达±120。