Efficient pattern modeling of plasmonic nanostructures probed by nanoscale near-field scanning microscope tips with different polarized outputs

摘要

We develop a method based on the reciprocity and Green function to efficiently obtain the far-field pattern of dipole emitters around plasmonic nanostructures. Applying this method to air hole arrays fabricated on metal films, we reveal their plasmonic characteristics in the near-field scanning optical microscopy. Modeling scanning-probe tips as surface plasmon launchers, we clarify the orientation effect of their equivalent dipoles and also how these effective dipoles contribute to the excitation of different plasmonic modes, resulting in distinguishable characteristics in the far-field imaging. The outcomes of our calculations are validated with the experimental data from a high-resolution raster scanning nano-focusing plasmonic tip. Satisfactory agreements between the model and measurements are demonstrated.