Design and Optimization of High- $Q$ Surface Mode Cavities on Patterned Metallic Surfaces

In this paper, we show that patterned metallic surfaces can support localized resonant modes if a suitable defect in the periodicity of the structure is introduced. For those modes, optical losses due to radiative leakage perpendicular to the metallic plane can be significantly reduced by properly tuning the geometry of the defect-mode surface cavity. A design strategy based on the investigation of the electromagnetic field in the reciprocal space is suggested.