Ultrathin 90-degree sharp bends for spoof surface plasmon polaritons

Abstract

Abstract:At low frequencies outside the plasmonic range, strongly confined surface waves can be achieved on periodically structured metal surfaces, thereby allowing for the design of compact electromagnetic guiding devices. Here, we propose an approach to realize highly efficient transmission of spoof surface plasmons around 90-degree sharp bends on ultrathin metallic films in the microwave regime. We demonstrate that by judiciously engineering the structure, the dispersion relation can be designed to reduce the scattering. Furthermore, the reflection can be suppressed by proper structural decoration at the bending corner. A onedimensional scattering theory is employed to understand and verify the transmission properties of our waveguide bend structure. Our design scheme is not restricted to the specific structure we propose here but can be applied to other guiding components built up on two dimensional metal surfaces. nanostructures containing blunt edges/corners: from symmetric to asymmetric edge rounding," ACS Nano 6(7), 6492-6506 (2012). 12. J. B. Pendry, Y. Luo, and R. Zhao, "Transforming the optical landscape," Science 348(6234), 521-524 (2015). 13. Y. Luo, R. Zhao, and J. B. Pendry, "van der Waals interactions at the nanoscale: the effects of nonlocality," Proc. ©2015 Optical Society of AmericaNatl. Acad. Sci. U.S.A. 111(52), 18422-18427 (2014). 14. J. B. Pendry, L. Martín-Moreno, and F. J. Garcia-Vidal, "Mimicking surface plasmons with structured surfaces,"Science 305(5685), 847-848 (2004). #241242Received 18

Integrated spoof plasmonic circuits

“…Ref. [36] demonstrates theoretically that the bending loss can be effectively reduced by increasing the confinement of EM fields in the spoof SPP TLs. Thus, the metamaterial feature offers us the freedom of achieving this goal by tuning the geometrical parameters of the spoof SPP structure.…”

Spoof surface plasmon polaritons based notch filter for ultra-wideband microwave waveguide

“…Generally, spoof SPP structures are composed by metal surfaces decorated with 1D arrays of sub wavelength grooves, 2D arrays of sub wavelength holes/dimples, or 3D metal wire in which a periodic array of radical grooves is drill [4,[10][11][12][13][14][15]. To solve the shortcomings in the fabrication and integration for most of the currently existing 3D spoof SPP structures, an ultrathin spoof SPPs one-dimensional grooves structure in the microwave frequencies has been proposed by Cui et al, which can be bent, twisted, and wrapped to arbitrary surfaces to produce conformal surface plasmons (CSPs) [5,[15][16][17][18][19][20][21][22]. And these structures have been used to design broadband planar and flexible SPP waveguide, 90 o bend, beam splitter, and ring resonator in the microwave frequency recently by Cui et al [21,[23][24][25].…”

“…The result shows that it has two sharp notched bands which are located at 5.36GHz and 9.32GHz with a 10 dB notched fractional bandwidth of 1.61%/1.29% and more than 20 dB rejection respectively. According to the reference [22], the dispersion curve of rectangle holes might be more deviated from the light line and Department of Photonics Engineering, Technical University of Denmark, Lyngby 2800, Denmark the cut-off frequency might be lower compared to rectangular groove, so rectangle holes were used here instead of grooves. Compared to the conventional structures (e.g.…”

Enhanced Transmissions Through Three-dimensional Cascade Sharp Waveguide Bends Using C-slit Diaphragms

“…In the meanwhile, controlling guided modes has also attracted large-scale attentions due to the increasingly quest for the more compact and miniaturized electromagnetic systems. Especially, waveguide bends, functioning as the basic components in the microwave and optical integrated circuits, have therefore always been a focus of the research activities that are exploring new potential configurations with sharper bending angles for the high packing density while possessing the merits of scarce reflections for the transmitting signals3456789101112131415161718192021222324252627.…”

“…In addition, photonic crystals are very competent in guiding and bending the electromagnetic fields, where perfect transmissions through sharp bends could be achieved by adjusting the length of the bend section212223. Especially, surface plasmon polaritons (SPPs) as a kind of quasi two-dimensional (2D) travelling modes sustaining at the interface between metals and air are also shown to be smoothly bended either by the transformation optics derived passages242526 or the ultrathin metallic films as a spoof SPPs travelling channel27. These modern technologies have greatly strengthened the controlling ability of the guided waves in many different scenarios compared with the conventional methods and provided promising applications for the compact electromagnetic circuits.…”