Strongly Localized and Strongly Enhanced Optical Near-Field Created by Surface Plasmon Polaritons and its Application in Nano-Phtonics

A metallic probe that provides a strongly localized and strongly enhanced optical near-field at the probe-tip has been investigated. Since the probe-tip is illuminated by SPPs inside the aperture, illumination by an external light is not necessary for this probe. It was found that the probe can create an optical near-field intensity that is about 10³ times larger than the incident intensity on the probe-tip, when appropriate parameters of the probe are used. The imaging simulation of a nanometric dielectric object by near-field scanning optical microscope (NSOM) using plasmonic gap probe proposed have been performed. Since the localization and enhancement of the optical near-field on the probe-tip is related to the propagation of SPPs in the nanometric gap inside the aperture and pyramidal structure, the phenomena investigated in this study are not simple. From our experience of numerical simulations, results are very sensitive to the various parameters of the aperture, demonstrating the need to develop accurate computer-aided design and simulation tools for the design of the probe