Versatile total angular momentum generation using cascaded J-plates (Conference Presentation)

Optical elements that couple the spin/orbital angular momentum (SAM/OAM) of light have found a range of applications in classical and quantum optics. The J-plate, which refers to the variable denoting the photon’s total angular momentum (TAM), is a metasurface device that allows converting arbitrary, orthogonal input SAM states into two unique OAM states. Using independent phase control of any orthogonal basis of polarization states, the J-plate permits the conversion of arbitrary polarizations into states with arbitrary OAM. Here, we present a further development: Cascaded J-plates provide for versatile combinations of OAM states on any orthogonal basis of spin states. J-plates operating on different polarization bases and imparting independent values of OAM are designed and experimentally demonstrated to generate multiple OAM channels with different polarization states. The generated OAM states are determined by the superposition of the OAM states of the individual J-plates while the generated SAM states are determined by the polarization basis of the last J-plate. Theoretically, there are maximum of 2^n channels of OAM and n×2^n channels of TAM that can be generated by n such cascaded J-plates. It is also demonstrated that cascaded J-plates may produce complex structured light. Cascading J-plates provides a new way to control the TAM of a laser beam. These results may find application in quantum and classical communication.