Spoof surface plasmon photonics

Structuring metallic surfaces allows for the support of surface electromagnetic modes at frequencies for which they would not be allowed for smooth surfaces. These modes are called ``spoof surface plasmons'' because of their similarity to surface plasmons that are supported at optical frequencies for smooth surfaces. This article describes the physics that underlies the behavior of spoof surface plasmons and how these modes are used in applications that require the manipulation of electromagnetic fields at frequencies below optical.