Spatial nonlocality effect on the surface plasmon propagation in plasmonic nanospheres waveguide

Area of Science:

• Plasmonics
• Nanophotonics
• Condensed Matter Physics

Background:

• Plasmonic nanostructures exhibit unique optical properties governed by electron oscillations.
• Spatial nonlocality, the dependence of material properties on electron wavevector, influences plasmon behavior at the nanoscale.
• Understanding these effects is crucial for designing advanced optical devices.

Purpose of the Study:

• To investigate the impact of spatial nonlocality on surface plasmon excitation energies and damping in metallic nanostructures.
• To analyze how spatial nonlocality affects plasmon interactions in coupled nanospheres and periodic chains.

Main Methods:

• Utilized the quasi-static hydrodynamic Drude model to calculate surface plasmon excitation energies.
• Phenomenologically incorporated surface scattering and radiation damping rates.
• Applied Bloch's theorem to analyze surface plasmon excitations in periodic nanosphere chains.

Main Results:

• Spatial nonlocality increases surface plasmon frequencies and damping rates in single nanospheres, especially for smaller sizes and higher multipole excitations.
• It reduces the interaction energy between adjacent nanospheres.
• In nanosphere chains, spatial nonlocality decreases group velocities and energy decay lengths of propagating plasmons.

Conclusions:

• Spatial nonlocality plays a significant role in the plasmonic characteristics of nanostructures, particularly for very small spheres and short interparticle distances.
• The findings provide insights into the design and behavior of plasmonic metamaterials and devices.