Direct method to control surface plasmon polaritons on metal surfaces.

The manipulation of surface plasmon polaritons (SPPs) on metal surfaces is an important aspect in the design of ultra-compact integrated micro/nano optical systems. We present a direct method for the easy, yet accurate design of complicated groove patterns to control SPPs traveling on metal surfaces, using a surface electromagnetic wave holography method, based on the Huygens-Fresnel principle. SPPs are scattered by these deliberately and appropriately determined groove patterns and interfere with each other to form new paths with desire. Two devices are demonstrated, with predesignated functionalities fully implemented by the designed plasmonic holographic structures, according to the finite-difference time-domain simulations. The results strongly indicate that this direct method is effective, efficient, and user friendly in its application to control SPPs on metal surfaces.