Plasmonic origami: tuning optical properties by periodic folding of plasmonic substrate: Gold's and graphene's cases

Surface plasmon polaritons (SPPs) have attracted great interest over the past decades, more recently graphene plasmon polaritons (GPPs) have renewed this interest owing to its electrical and optical properties, such as electrically tunable property, extreme confinement, ultrabroad tuning spectrum, and low intrinsic loss. While many have focused on the planar structure of graphene, in this work we introduce a novel plasmonic metasurface based on the periodic folding of polaritonic material considered as 2D. In this work the case of a gold nano-layer is also presented. The fabrication procedure can be broken down into two main parts: first, the fabrication of a W- shaped silicon (Si) matrix, and second, the use of this matrix to mold a gold film or to deform a monolayer graphene by transfer. As a result, tailored periodic is widely implemented to produce localized surface plasmon resonances (LSPRs). We found that the proposed structures exhibits strong and tunable resonances in broad spectral range, and that the folding angle play a critical role.

A geometry-induced quasi-omnidirectional or directional absorption is notably observed. Finally, the devices were fabricated, and spectrometers were used to optically characterize their plasmonic resonance behavior. Our research paves the way for applications of passive/active plasmonic circuits and metamaterials from visible to THz regimes, leading to a new application for optical sensors and photovoltaic cells in passive/active devices from the visible to the THz regimes.