(a) Plasmonic splitter based on pin cushion structures. Reprinted from reference [70] with permission. (b) Leakage radiation image of SPPs from a plasmonic splitter based on concentric nanostructures. Inset shows the SEM image. Reprinted from reference [27] with permission. (c) Simulation of SPP fields from a binary plasmonic splitter. Inset shows the schematic of the binary structure. Reprinted from reference [28] with permission.