Dielectric meta-walls for surface plasmon focusing and Bessel beam generation

Freely tailoring the wavefronts of surface plasmon polaritons (SPPs) is a central goal in plasmonics, but the conventional approaches exhibit low efficiencies and/or require bulky devices. Here, we propose to utilize ultrathin dielectric meta-walls placed vertically on a plasmonic metal to efficiently reshape the wavefront of a launched SPP beam. Based on such a strategy, we experimentally demonstrate two effects in the microwave regime, namely focusing and Bessel beam generations of spoof SPPs. Near-field scanning measurements are in excellent agreement with full wave simulations. This work can stimulate research in many applications related to SPP manipulations, such as enhanced nonlinear effect, nano-particle trapping, and so on.