Electrical Control of Optical Plasmon Resonance with Graphene
CALIFORNIA UNIV BERKELEY DEPT OF PHYSICS
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Surface plasmon has the unique capability to concentrate light into subwavelength volume. Active plasmon devices using electrostatic gating can enable flexible control of the plasmon excitations,6 which has been demonstrated recently in terahertz plasmonic structures. Controlling plasmon resonance at optical frequencies however, remains a significant challenge because gate-induced free electrons have very weak responses at optical frequencies. Here we achieve efficient control of nearinfrared plasmon resonance in a hybrid graphene-gold nanorod system. Exploiting the uniquely strong and gate-tunable optical transitions of graphene, we are able to significantly modulate both the resonance frequency and quality factor of gold nanorod plasmon. Our analysis shows that the plasmon-graphene coupling is remarkably strong even a single electron in graphene at the plasmonic hotspot could have an observable effect on plasmon scattering intensity. Such hybrid graphene-nanometallic structure provides a powerful way for electrical control of plasmon resonances at optical frequencies and could enable novel plasmonic sensing down to single charge transfer events.
- Industrial Chemistry and Chemical Processing
- Inorganic Chemistry
- Physical Chemistry