Abstract

Plasmonic Metasurfaces (PMs) offer unprecedented ways to manipulate optical wavefronts with an ultra-thin layer of materials. Until recently, the research efforts have focused on designing passive metasurfaces. However, gaining high-speed, reversible control over individual pixels (basic building block) in these engineered structures can offer better and faster ways to control and shape light. Conventionally used tuning approaches target the whole substrate by either utilizing mechanically moving frames or tuning the refractive index of the whole substrate. Conceptualizing a high-speed, switching mechanism for locally tuning pixel/meta-atom will allow new applications that were previously unimaginable. Here we introduce a novel approach for tunable plasmonic meta-atoms via modulation doping in semiconductor nanostructures at the telecommunication window which can potentially be used for local control in PMs. The proposed approach is based on (voltage-controlled) tuning the quantum confinement of the charge carrier from 1-D to 0-D in semiconductor nanorods. The applied field allows accumulation of excess charge carrier density and facilitates tuning plasmonic resonance of nanoresonators from 1800–1550 nm. A high-speed voltage-controlled localized surface plasmon resonance is reported in semiconductor nanostructures fabricated via a cost-effective, scalable, self-assembly process based on aluminum anodization. Moreover, the concept in-principle will be compatible with most semiconductors allowing exciting applications in tunable metasurfaces, spasers, modulators, and many more.