Journal Article metasurfaces Pancharatnam-Berry phase Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. circular dichroism grafted vortex beams holographic multiplexing imaging metalenses multiple channels nonlinear imaging nonlinear optics optical data storage, metamaterials optical metasurfaces optical perfect vortex beams plasmonic second harmonic generation superposition of grafted vortex beams