Direct Near-Field Optical Imaging of Higher Order Plasmonic Resonances
Journal article, 2008
We map in real space and by purely optical means near-field optical information of localized surface plasmon polariton (LSPP) resonances
excited in nanoscopic particles. We demonstrate that careful polarization control enables apertureless scanning near-field optical microscopy
(aSNOM) to image dipolar and quadrupolar LSPPs of the bare sample with high fidelity in both amplitude and phase. This establishes a
routine method for in situ optical microscopy of plasmonic and other resonant structures under ambient conditions.