Fig. 3
From: Phyllotaxis-inspired nanosieves with multiplexed orbital angular momentum
Plasmonic phyllotaxis-inspired vortex nanosieve. a A plasmonic phyllotaxis-inspired vortex nanosieve which can yield three plasmonic vortex modes upon circular polarization states. The stereoscopic ‘hot’ map of the intensity distribution of the z component of the SPP (surface plasmon polariton) wave is depicted above the sample surface. The red and blue solid circles and dotted lines mark the trajectories of two hidden spiral patterns which can be encoded from the structure. The two sets of hidden spiral patterns can excite plasmonic vortices at l = 40(\(\pm 1\)), 80(\(\pm 1\)) upon circular polarizations. b A top-view SEM image of the sample. The radius of each nanohole is 150 nm. c, d The simulated intensity (c) and phase (d) profiles of generated plasmonic vortex modes excited by RCP, LCP, and LP illumination, respectively. e, Measured intensity profiles of the generated plasmonic vortex modes upon RCP, LCP and LP illumination