The cover illustrates a structured optical field, dubbed a flower‐shaped optical vortex array by Xinzhong Li and co‐workers in article number 2000575. The inner layer uses a clock to represent the phase change, the hour hand represents the phase of the even IG beam, and the minute hand represents the phase of the odd IG beam. The outer layer is a specific example of an optical field, which keeps the phase of the odd IG beam unchanged, and changes the phase of the even IG beam, As the phase difference between the even mode IG beam and the odd mode IG beam increases, the optical field rotates gradually.

中文翻译：

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光场：花形旋涡阵列（物理物理学4/2021）

封面显示了一个结构化的光场，由李新中及其同事在文章编号2000575中称为花形光涡旋阵列。内层使用时钟表示相变，时针表示偶数IG的相位分针代表奇数IG光束的相位。外层是光场的特定示例，其保持奇数IG光束的相位不变，并改变偶数IG光束的相位，随着偶数模式IG光束和奇数IG光束之间的相位差增大，光场逐渐旋转。