Electrical Tuning of Surface Plasmon Polariton Propagation in Graphene-Nanowire Hybrid Structure

Due to the ability to produce highly enhanced optical fields below the diffraction limit, surface plamon polariton(SPP) has wide scientific and technological applications. It is desired to have the ability to dynamically manipulate SPPs for their practical applications in modern information and communication technologies, preferably by applying an electrical bias. However, even noble metals, which are widely regarded as the best candidate for plasmonic materials, are hardly tunable simply through electrical operation partially because of the difficulties in changing the carrier density. Prof. Qing Yang’s group demonstrates a dynamic surface plasmonic modulation based on grapheme-nanowire (grapheme-NW) hybrid structures in the visible light range. Through careful simulation and systematical experimental investigation, they found that the dual-confinement effect of charge density and electromagnetic energy around the vicinity of the NW will dramatically enhance the light-matter interaction and increase the Fermi level shifting, which are the key roles for bringing the optical response of the device to the visible range. As the SPP mode area can be further squeezed, the device may provide a way of fabricating ultracompact nanophotonic devices and may find its applications in integrated optical circuits, nanoscaled laser sources, optical communications, etc. The paper was published on <ACS Nano>, [ACS Nano 8, 2584–2589 (2014). And the paper was selected by the editor as “ACS Editors’ Choice”. The first author Haoliang Qian was honored the best 100 bachelor degree thesis.