Mode Splitting Induced by Mesoscopic Electron Dynamics in Strongly Coupled Metal Nanoparticles on Dielectric...

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Metal nanoparticle arrays exhibit strong optical coupling with dielectric substrates.
• Understanding particle-substrate interactions is crucial for optimizing optoelectronic devices.

Purpose of the Study:

• To investigate strong optical coupling in metal nanoparticle-dielectric substrate systems.
• To analyze the impact of nonlocal electron dynamics on optical properties.
• To explain observed phenomena like Autler-Townes splitting and photocurrent enhancement.

Main Methods:

• Derivation of particle-substrate coupling using Fermi Golden Rule and local dipole approximation.
• Application of nonlocal hydrodynamic theory for mesoscopic electron dynamics.
• Numerical simulations using COMSOL integrating derived equations.

Main Results:

• Optical coupling increases photocurrent gain.
• Nonlocal electron dynamics significantly enhance absorption and scattering cross-sections for nanoparticles <20 nm.
• Observation of optical mode splitting, indicative of Autler-Townes splitting.
• Simulated photocurrent increase up to 2%, showing improved agreement with experiments.

Conclusions:

• Strong optical coupling and nonlocal effects are key to understanding nanoparticle array performance.
• The developed theoretical framework and simulations provide accurate predictions for photocurrent generation.
• This work offers insights into optimizing plasmonic nanostructures for enhanced light-matter interactions.