Surface plasma discharge generated by spoof surface plasmon polariton excitation: a computational modeling study

Abstract

We discuss a computational modeling study of surface plasma generation by spoof surface plasmon polariton (SSPP) mode excitation of a corrugated metal surface. The SSPP mode is a highly localized electromagnetic wave propagating along the interface between a conductor and dielectric. The corrugations are defined by an array of rectangular cavities (comb structures) in the metal at the location of the interface. Spoof plasmon resonances occurring at each cavity couple with one another at the interface to produce localized surface wave structures whose wavelength can be much smaller than the incident wave. The electromagnetic wave structure for a finite length of the interface (metasurface) is analytically estimated and its correlation to the resonance frequency of the infinite metasurface is studied numerically. Strong local enhancement of the electromagnetic fields at the metasurface is used to initiate the plasma breakdown of pure argon gas at 10 Torr. Confined microdischarges produced initially at each of the comb structure evolve rapidly to create an extended structure of high density ~1019 m−3 surface plasma whose properties are comparable to surface streamers generated in dielectric barrier discharges.