Light confinement and propagation characteristics in plasmonic gap waveguides on silicon
Résumé
Plasmonic waveguiding structures have the ability to confine and propagate light over short distances, typically less than a hundred micrometers. This short propagation length is the price that is paid for confininglight to dimensions on the order of a hundred of nanometers. With these scales in mind, several plasmonic devices can be proposed (e.g. wavelength multiplexors) and some of them have been already demonstrated such as Y junctions and directional couplers. Although the dimensions involved in such structures are below the diffraction limit, large-scale optical characterization techniques, such as transmitted power, are still employed. In this contribution, we present a characterization technique for the study of the guided modes in plasmonic gap waveguiding structures that resolves subwavelength-scale features, as it is based on atomic force microscope and on near field scattering optical microscope in guided detection.