Nanostructures for Twisted Light
For practical applications of orbital angular momentum (OAM) states, a simple approach is highly desirable for the generation of OAM beams and the manipulation of their superpositions in multiple channels. A facile metasurface approach is experimentally demonstrated by Dr. X. Chen and his research team to realise polarization-controllable multichannel superpositions of OAM states at will. By manipulating the polarization state of the incident light, arbitrary control of the superpositions of various OAM states in multiple channels is realized using a single plasmonic metasurface.