Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to–orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication.

中文翻译：

---

光的任意自旋至轨道角动量转换

将光的自旋角动量（SAM）转换为涡旋光束的光学元件已在经典光学和量子光学中得到应用。这些元素-SAM到轨道角动量（OAM）转换器-基于几何相位，并且仅允许将左旋和右旋圆偏振（自旋状态）转换为具有相反OAM的状态。我们提出了一种将任意SAM状态转换为以独立OAM叠加为特征的总角动量状态的方法。我们设计了一个超表面，可以将左右圆偏振转换为具有独立OAM值的状态，并设计了另一种对椭圆偏振状态执行此操作的设备。