Direct characterization of plasmonic slot waveguides and nanocouplers

TL;DR

This paper presents a method for directly characterizing plasmonic slot waveguides and nanocouplers using near-field mapping, revealing significant improvements in coupling efficiency with specific antenna configurations.

Contribution

It introduces a direct measurement technique for waveguide modes and demonstrates substantial efficiency enhancements with novel nanocoupler designs.

Findings

Measured propagation length, effective index, and field distribution.

Achieved 26-fold and 15-fold improvements in coupling efficiency.

Demonstrated effective nanocoupler configurations.

Abstract

We demonstrate the use of amplitude- and phase-resolved near-field mapping for direct characterization of plasmonic slot waveguide mode propagation and excitation with nanocouplers in the telecom wavelength range. We measure mode's propagation length, effective index and field distribution and directly evaluate the relative coupling efficiencies for various couplers configurations. We report 26- and 15-fold improvements in the coupling efficiency with two serially connected dipole and modified bow-tie antennas, respectively, as compared to that of the short-circuited waveguide termination.