Zheng Sen, Hao Honggang, Tang Yihao, Ran Xuehong
Opt Lett. 2021 Dec 1;46(23):5790-5793. doi: 10.1364/OL.441426.
In this Letter, we propose an approach to generate high-purity orbital angular momentum (OAM) vortex waves using an amplitude-and-phase metasurface (APM). By varying the square split ring opening and orientation angles, the cross-polarized reflection response of the proposed structure can yield full phase and amplitude coverage. Based on the traditional phase-only metasurface (POM), the Chebyshev synthesis method (CSM) is applied to array the metasurface amplitude distribution. Metasurfaces with modes of 1, 2, 3, and 4 are designed. Compared with the POM, the APM can effectively improve the vortex beam quality and OAM mode purity. The measured results agree well with full-wave simulations. The presented method provides a new, to the best of our knowledge, way to design high-purity OAM generators based on metasurfaces.
在本信函中，我们提出了一种利用幅度和相位超表面（APM）生成高纯度轨道角动量（OAM）涡旋波的方法。通过改变方形裂环的开口和取向角度，所提出结构的交叉极化反射响应可实现全相位和幅度覆盖。基于传统的纯相位超表面（POM），应用切比雪夫合成方法（CSM）对阵超表面的幅度分布。设计了模式为1、2、3和4的超表面。与POM相比，APM可有效提高涡旋光束质量和OAM模式纯度。测量结果与全波模拟结果吻合良好。据我们所知，所提出的方法为基于超表面设计高纯度OAM发生器提供了一种新途径。
