  Scattering scanning near-field optical microscopy enables optical imaging and
characterization of plasmonic devices with nanometer-scale resolution well
below the diffraction limit. This technique enables developers to probe and
understand the waveguide-coupled plasmonic antenna in as-fabricated
heat-assisted magnetic recording heads. In order validate and predict results
and to extract information from experimental measurements that is physically
comparable to simulations, a model was developed to translate the simulated
electric field into expected near-field measurements using physical parameters
specific to scattering scanning near-field optical microscopy physics. The
methods used in this paper prove that scattering scanning near-field optical
microscopy can be used to determine critical sub-diffraction-limited dimensions
of optical field confinement, which is a crucial metrology requirement for the
future of nano-optics, semiconductor photonic devices, and biological sensing
where the near-field character of light is fundamental to device operation.
