Imaging Near-Field Surface Plasmon Polaritons Launched by Nano-Emitters.

Researchers at the University of Pennsylvania have used tip-enhanced nanospectroscopy to study surface plasmon polaritons (SPPs) in nano-emitters in the near field. The technique allowed the team to visualize spatial and spectral properties of the propagating SPPs, which could lead to exciting new practical plasmonic devices. The researchers found that the electric-field intensity varied periodically as the distance between the tip and the nanoplatelet was increased, confirming the presence of a standing wave and demonstrating how the nanoplatelet and tip act as a kind of cavity.