Symmetrical estimation method for skin depth control of spoof surface plasmon polaritons using dispersed waves from a metallic hole array

A metallic hole array (MHA) supports the propagation of spoof surface plasmon polariton (SSPP) modes on its surface. We observe enhancement of dispersed waves at a specific angle when SSPP modes propagate. We propose a symmetrical estimation method for SSPP skin depth using waves dispersed from an MHA. The proposed method provides an experimental demonstration of the skin depth of the electric fields of SSPP modes. Using the dispersed waves emitted from the plane of the MHA, we are able to detect confined electric fields with decay lengths that resemble those theoretically predicted around a specific frequency of SSPP mode excitation.