Plasmonic lenses for wavefront control applications using two-dimensional nanometric cross-shaped aperture arrays

Localized surface plasmon resonances occurring within subwavelength apertures are accompanied by an aperture-geometry-dependent phase shift that can be utilized for beam manipulation. Here we demonstrate two-dimensional, planar, converging and diverging plasmonic lenses, formed by an array of nanometric spatially varying cross-shaped apertures in a silver film. The performance of lenses with different design configurations was evaluated at two different wavelengths using a confocal scanning optical microscope.