Functional plasmonic nano-circuits with low insertion and propagation losses

TL;DR

This paper demonstrates efficient, low-loss plasmonic nano-circuits using optical antennas and gap waveguides, enabling high-performance sub-diffraction optical components at 1550 nm.

Contribution

The work introduces a novel integration of optical Yagi-Uda antennas with plasmonic waveguides for low-loss, high-efficiency nano-circuits with compact directional couplers.

Findings

Achieved 45% coupling efficiency from free space to waveguides.

Demonstrated propagation lengths up to 34 μm in SPP gap waveguides.

Realized 30 dB discrimination with only 0.3 dB device loss.

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 \lambda = 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{\deg}) and low insertion loss. SPP gap waveguides exhibit propagation lengths as large as 34 {\mu}m with adiabatically tuned confinement, and are integrated with ultra-compact (5 \mu m x 10 \mu m), highly dispersive directional couplers, which enable 30 dB discrimination over {\Delta}{\lambda} = 200 nm with only 0.3 dB device loss.