Directive antenna nanocoupler to plasmonic gap waveguides.

Area of Science:

• Photonics
• Plasmonics
• Nanotechnology

Background:

• Optical nanocouplers are crucial for integrating fiber and plasmonic nanowaveguides in nanophotonic systems.
• Existing nanocouplers often lack efficiency due to size mismatches and non-directive designs.

Purpose of the Study:

• To design an efficient optical nanocoupler for visible light (λ0=0.65 μm).
• To maximize coupling efficiency (CE) by optimizing a directive nanoantenna and its matching element.

Main Methods:

• Design and optimization of a directive nanoantenna.
• Utilizing localized plasmonic resonance for high-frequency operation.
• Comparative analysis against nondirective antenna nanocouplers.

Main Results:

• Achieved high coupling efficiency with a compact nanoantenna.
• The directive nanoantenna design improved CE by a factor of 10.
• Demonstrated efficient coupling despite the small antenna size relative to the fiber spot size.

Conclusions:

• Directive nanoantennas are effective for enhancing optical nanocoupler performance.
• Optimized nanocouplers offer a significant improvement for nanophotonic applications.
• This design overcomes limitations of previous nondirective approaches.