Coupled dipole approximation across the Γ-point in a finite-sized nanoparticle array

Area of Science:

• Nanophotonics
• Condensed Matter Physics
• Computational Electromagnetics

Background:

• Nanoparticle arrays exhibit unique optical properties.
• Understanding their response to incident fields is crucial for nanophotonic applications.
• Lattice resonances, particularly near the Γ-point, significantly influence optical behavior.

Purpose of the Study:

• To investigate the optical response of finite-sized nanoparticle arrays near the lattice Γ-point.
• To analyze the spatial distribution of induced dipoles.
• To examine the resulting extinction efficiencies and radiation patterns.

Main Methods:

• Utilizing the coupled dipole approximation (CDA) for numerical simulations.
• Analyzing the incident field's interaction with the nanoparticle array.
• Calculating real-space extinction efficiencies and far-field radiation patterns.

Main Results:

• Observed strongly inhomogeneous dipole distributions within the array.
• Identified significant modulations in optical properties when the energy is above the Γ-point.
• Demonstrated a clear link between dipole inhomogeneity and observable extinction efficiencies and radiation patterns.

Conclusions:

• Finite-sized nanoparticle arrays exhibit complex optical responses near the Γ-point.
• The coupled dipole approximation effectively captures inhomogeneous dipole distributions and their consequences.
• Results provide insights into controlling light-matter interactions in nanophotonic systems.