Near-Field Characterization Of Surface Plasmon Polaritons On A Nanofabricated Transmission Structure

The tailoring of plasmonic near fields is central to the field of nanophotonics. Detailed knowledge of the field distribution is crucial for design and fabrication of plasmonic sensors, detectors, photovoltaics, plasmon-based circuits, nanomanipulators, electro-optic plasmonic modulators, and atomic devices. We report on a quantitative comparison between near-field observation and numerical calculations, considering the intensity distribution for transverse magnetic (TM) and transverse electric (TE) polarizations, which are necessary for the construction of devices in all these areas. We present the near-field scanning microscopy (NSOM) results of surface plasmon polaritons (SPPs), excited by linearly polarized illumination on a gold, nanofabricated transmission grating. The optimization process is performed for infrared light for applications in cold-atom trapping and plasmonic sensing. We show the in situ processes of buildup and propagation of SPPs and confirm that the out of plane component of the electric field is not coupled to the aperture-type NSOM probe.