Coherent imaging of nanoscale plasmon patterns with a carbon nanotube optical probe

Abstract

We introduce a carbon nanotube as optical near-field probe and apply it to visualize the plasmon fields of metal nanostructures in both amplitude and phase at 30 nm resolution. With 91 nm Au disks designed for fundamental plasmon resonance, we observe the antiphase optical fields near two pole regions that are evidence of dipolar oscillation, in good agreement with theoretical field patterns. This opens the door to phase-sensitively map optical propagation and storage in photonic crystals and nanooptic resonators or circuits, in particular to verify coherent control of plasmon polaritons.