Analysis of mutual couplings in a concentric circular ring plasmonic optical antenna array

Area of Science:

• Plasmonics
• Optical Antennas
• Electromagnetics

Background:

• Plasmonic optical antennas (POAs) are crucial for manipulating light at the nanoscale.
• Understanding near-field interactions is essential for designing efficient POA arrays.
• Previous models often simplify or overlook complex coupling effects.

Purpose of the Study:

• To develop and validate a simple lumped coupled circuit (LCC) model for analyzing concentric circular ring plasmonic optical antenna (POA) arrays.
• To investigate the mutual coupling effects between antenna elements in a POA array.
• To establish the LCC model as a tool for near-field analysis in POA arrays.

Main Methods:

• Development of a lumped coupled circuit (LCC) model to represent the POA array.
• Analysis of current distributions and mutual couplings within the circular rings using the LCC model.
• Validation of LCC model results against numerical simulations (CST's Microwave Studio®).

Main Results:

• The LCC model accurately predicts the behavior of the circular ring POA array, showing good agreement with simulations.
• Significant mutual couplings were identified not only between adjacent rings but also with second and farther neighbors.
• The model demonstrates that near-field interactions are directly related to the current distributions in the antenna rings.

Conclusions:

• The simple LCC model provides an effective and computationally efficient method for analyzing circular ring POA arrays.
• The study highlights the importance of considering long-range mutual couplings for accurate near-field predictions.
• The LCC model serves as a valuable tool for the design and optimization of complex plasmonic optical antenna systems.