title: Conformal surface plasmons propagating on ultrathin and flexible films.
abstract: Surface plasmon polaritons (SPPs) are localized surface electromagnetic waves that propagate along the interface between a metal and a dielectric. Owing to their inherent subwavelength confinement, SPPs have a strong potential to become building blocks of a type of photonic circuitry built up on 2D metal surfaces; however, SPPs are difficult to control on curved surfaces conformably and flexibly to produce advanced functional devices. Here we propose the concept of conformal surface plasmons (CSPs), surface plasmon waves that can propagate on ultrathin and flexible films to long distances in a wide broadband range from microwave to mid-infrared frequencies. We present the experimental realization of these CSPs in the microwave regime on paper-like dielectric films with a thickness 600-fold smaller than the operating wavelength. The flexible paper-like films can be bent, folded, and even twisted to mold the flow of CSPs.
authors.affiliation: State Key Laboratory of Millimetre Waves, School of Information Science and Engineering,  Southeast University, Nanjing 210096,  China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Shen
authors.forename: Tie Jun
authors.initials: TJ
authors.lastname: Cui
authors.forename: Diego
authors.initials: D
authors.lastname: Martin-Cano
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Garcia-Vidal
mesh_terms: D060733:Electromagnetic Radiation; D008670:Metals / Q000737:chemistry*; D008872:Microwaves; D055095:Optics and Photonics / Q000295:instrumentation* / Q000379:methods; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D008670:Metals