Design and Numerical Analyses of Ultrathin Plasmonic Lens for Subwavelength Focusing by Phase Discontinuities of Nanoantenna Arrays

A novel ultrathin plasmonic lens is designed and numerically simulated to analyze its focusing performance. The lens is constructed of planar arrays of a plasmonic nanoantenna. A discontiguous phase distribution can be realized by appropriate design of the resonance of nanoantennas. Both one-dimensional (1D) linearly and two-dimensional (2D) circularly arranged lens structures are realized, which focus the cross-polarized light at an arbitrary focal length. Furthermore, both the refracted and reflected light can be focused, which is distinctly different from the conventional lens. All these unique performances give this lens great potential for applications in integrated optical systems. (C) 2013 The Japan Society of Applied Physics