Surface-wave pulse routing around sharp corners

TL;DR

This paper demonstrates a simple metallic cylinder array that acts as a surface-wave photonic crystal, enabling near-perfect guiding of surface waves around sharp corners without back-scattering or radiation, with applications in splitting and resonators.

Contribution

It introduces a novel photonic structure that allows surface waves to navigate ultra-sharp corners and splitters with minimal loss, overcoming fundamental wave-mismatch challenges.

Findings

Near-perfect transmission of surface waves around sharp corners.

Efficient T-shaped splitter for surface waves.

High-Q plasmonic open resonator achieved.

Abstract

The ability to perfectly guide surface electromagnetic waves around ultra-sharp corners without back-scattering and radiation is in great demand for various photonic and plasmonic applications. This is fundamentally difficult to realize because of the dramatic momentum mismatch and wave nature of radiation at the sharp corners. Here we experimentally demonstrate that a simple photonic structure, a periodic square array of metallic cylinders standing on a metal surface, can behaves as a surface-wave photonic crystal with complete photonic band gap to overcome this bottleneck simply. A line-defect waveguide can support and guide surface waves around ultra-sharp corners without perceptible radiation and reflection, achieving almost perfect transmission efficiency in a broad frequency range. We also demonstrate an ideal T-shaped splitter to split input surface waves equally into two arms and a square radiation-suppressed plasmonic open resonator with high quality factors by simply inducing line-defects in this fully open surface-wave photonic crystal.