Optical Ultracompact Directional Antennas Based on a Dimer Nanorod Structure.

Area of Science:

• Nanophotonics and Plasmonics
• Optical Engineering
• Materials Science

Background:

• Controlling optical emitter directionality is crucial for communication and biosensing.
• Metallic nanoantennas can modify emitter properties, including emission directionality.
• Existing Yagi-Uda nanoantennas are large and complex, hindering nanophotonic integration.

Purpose of the Study:

• To investigate an ultracompact optical antenna design for directional light emission.
• To overcome the size and complexity limitations of traditional nanoantennas.
• To assess the feasibility and robustness of a side-to-side gold nanorod dimer antenna.

Main Methods:

• Numerical simulation of an ultracompact optical antenna composed of two parallel gold nanorods.
• Analysis of the antenna's performance when excited by a nearby nanoemitter.
• Parametric study including nanorod shape, dimer defects, and nanoemitter placement/orientation.

Main Results:

• The excitation of the antiphase mode in the side-to-side dimer antenna enables directional emission.
• The ultracompact design shows robustness to structural variations and nanoemitter positioning.
• Simulations confirm the potential for controlled directional emission with this antenna configuration.

Conclusions:

• The ultracompact side-to-side gold nanorod dimer antenna is a promising alternative for directional emission control.
• This design is robust to fabrication imperfections and emitter placement variations.
• The findings support the suitability of this antenna for experimental upscaling and nanophotonic applications.