We demonstrate the use of amplitude- and phase-resolved near-field mappingfor direct characterization of plasmonic slot waveguide mode propagation andexcitation with nanocouplers in the telecom wavelength range. We measure mode'spropagation length, effective index and field distribution and directlyevaluate the relative coupling efficiencies for various couplersconfigurations. We report 26- and 15-fold improvements in the couplingefficiency with two serially connected dipole and modified bow-tie antennas,respectively, as compared to that of the short-circuited waveguide termination.
展开▼
