Plasmon resonance modes in two-dimensional arrays of metallic nanopillars

Surface plasmon polaritons (SPPs) and localized plasmon resonance modes in two-dimensional arrays of silver nanopillars on silver surface were analyzed using the three-dimensional finite-difference time domain method. What we believe to be a new type of plasmon resonance modes at oblique incident angle for p-polarized light was observed in two-dimensional arrays of silver nanopillars in a square lattice. This resonance mode is associated with two SPP-like electric field patterns along the metal surface. We found that this resonance mode is localized and excited by the transverse polarization mode of nanopillars. Using Poynting vector plots, it was observed that the plasmon resonances in arrays of nanopillars are always associated with large energy cyclones near the nanopillars leading to light absorption. (C) 2010 Optical Society of America