Routing of strongly confined terahertz spoof surface plasmon polaritons on metasurfaces along straight and curved pathways with subwavelength width

Abstract

In search of new technologies for optimizing the performance and space requirements of electronic and optical micro-circuits, the concept of spoof surface plasmon polaritons (SSPPs) has come to the fore of research in recent years. Due to the ability of SSPPs to confine and guide the energy of electromagnetic waves in a subwavelength space below the diffraction limit, SSPPs deliver all the tools to implement integrated circuits with a high integration rate. However, in order to guide SSPPs in the terahertz frequency range, it is necessary to carefully design metasurfaces that allow one to manipulate the spatio-temporal and spectral properties of the SSPPs at will. Here, we propose a specifically designed cut-wire metasurface that sustains strongly confined SSPP modes at terahertz frequencies. As we show by numerical simulations and also prove in experimental measurements, the proposed metasurface can tightly guide SSPPs on straight and curved pathways while maintaining their subwavelength field confinement perpendicular to the surface. Furthermore, we investigate the dependence of the spatio-temporal and spectral properties of the SSPP modes on the width of the metasurface lanes that can be composed of one, two or three cut-wires in the transverse direction. Our investigations deliver new insights into downsizing effects of guiding structures for SSPPs.

Plasmonics for Telecommunications Applications

“…It is worth mentioning that these electromagnetic surface modes are named spoof surface plasmon polaritons (SSPP) as they mimic the optical SPR properties [173,174]. Although SSPPs are used in telecommunications for several applications like antennas [175][176][177] and transmission lines [178,179], they have shown an exceptional ability for highly efficient wavelength filtering [180,181]. Other filters' approaches include hexagonal [182,183] and ring resonators [184], as the one illustrated in Figure 4c, enabling easy tuning of rejection-band at mid-infrared frequencies by simply varying the ring's radius.…”