A Review of Terahertz Plasmonics in Subwavelength Holes on Conducting Films

In this paper, we present a review of experimental studies of terahertz plasmonic transmission properties through subwavelength holes patterned in conducting films. The frequency-dependent transmission spectrum reveals resonant behavior with an anomalously high peak transmission which is mediated by the excitation of surface plasmon polaritons. We show how terahertz time-domain spectroscopy has been utilized to determine the resonant transmission effects of hole shape, dielectric properties of materials, and thickness of the arrays. Enhanced terahertz transmission was also observed through a single hole, accompanied by annular periodic corrugations. In addition to metals films, we review films comprised of highly doped semiconductors and superconductors. We finally review various modulation schemes to actively control or manipulate the resonant terahertz transmission using external stimuli such as thermal, optical, and electrical fields. This body of work is used to provide perspective on how manipulation of terahertz radiation via surface plasmon polaritons could affect next-generation terahertz photonic devices.