Functional plasmonic nano-circuits with low insertion and propagation losses

Abstract

We experimentally demonstrate plasmonic nano-circuits operating as sub-diffraction directional couplers optically excited with high efficiency from free-space using optical Yagi-Uda style antennas at λ= 1550 nm. The optical Yagi-Uda style antennas are designed to feed channel plasmon waveguides with high efficiency (45 % in coupling, 60 % total emission), narrow angular directivity (< 40°) and low insertion loss. SPP gap waveguides exhibit propagation lengths as large as 34 μm with adiabatically tuned confinement, and are integrated with ultra-compact (5 μm x 10 μm), highly dispersive directional couplers, which enable 30 dB discrimination over Δλ = 200 nm with only 0.3 dB device loss.

10 pages, 7 figures, additional supplementary information available