Wideband plasmonic focusing metasurfaces

We present a technique for designing wideband focusing metasurfaces. The proposed metasurface consists of unit cells of nanoparticle-based spatial phase shifters distributed over a planar surface. The topology of each spatial phase shifter is based on the design of plasmonic frequency selective surfaces. A true ab-initio design procedure for the proposed reflectarray is also proposed for the desired bandwidth and center frequency. A reflectarray for focusing the entire red spectrum (75 nm) is designed, with full-wave simulation results demonstrating desired focusing.