Optical and terahertz near-field studies of surface plasmons in subwavelength metallic slits

Abstract

We studied the transmission of the electromagnetic waves through subwavelength slit arrays in terahertz (THz) and optical frequency regions, respectively. In the optical frequency regime, the influences of surface plasmon polaritons on the near-field distribution and on the far-field transmittance are discussed. The near-field electro-optic sampling technique combined with fast Fourier transformation is applied in measuring the THz near-field distribution in time and spectral domains. From these, we discuss the existence of highly confined surface waves in the perfect conductor regime (THz) in comparison with the finite conducting case (visible range) in metallic multi-slit arrays. Our studies provide an integrated view of surface plasmons in the optical regime, and surface-bound waves mimicking surface plasmons in the THz region. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.