1 nm resolution imaging of localized plasmons via field rectification

We demonstrate the application of a scanning tunneling microscope to image localized plasmons excited on nanoscale gaps and crevices making up the gold nanoplasmonic antenna surface. The localized plasmon field is imaged directly with an unprecedented high resolution of 1 nm. Our experiments attest that the observed tunnel current signal is due to the localized plasmon field alone, which is detected as a rectified signal at in the nonlinear tunneling junction. This method has the potential for direct sub-nanometer imaging of localized plasmon fields. (C) 2013 AIP Publishing LLC.