Total Angular Momentum Sorting with a Silicon Metasurface Based Spiral Transformation Scheme

As joint multiplexing/encoding of orbital angular momentum (OAM) and spin angular momentum (SAM) states in theory can further enhance the functionality and capacity of optical information systems, it is desirable and critical to achieve total angular momentum sorting of light. In this work, a silicon metasurface-based spiral transformation scheme is proposed and demonstrated to achieve this goal, which can be theoretically lossless and low-crosstalk. Therefore, it could be useful in both classical and quantum information systems exploiting the framework of high-dimensional OAM-SAM multiplexing.