Nonlocal effects investigation via the coupling between localized and acoustic plasmons

Area of Science:

• Condensed matter physics
• Plasmonics
• Nanophotonics

Background:

• Nonlocal effects in metals significantly alter plasmonic properties, especially under strong field confinement.
• Acoustic plasmons (APs) in graphene-metal systems exhibit different dispersions depending on whether nonlocal responses are considered.
• Graphene plasmons (GPs) offer strong field confinement, making them suitable for probing these effects.

Purpose of the Study:

• To propose and investigate a scheme for studying nonlocal effects in metals.
• To leverage the coupling between localized graphene plasmons (GPs) and acoustic plasmons (APs).
• To develop a method for extracting nonlocal effects from experimental spectra.

Main Methods:

• Utilizing a graphene nanoribbon array to couple incident light to localized GPs.
• Inducing strong coupling between GPs and APs, analogous to electric field dipole interaction.
• Analyzing absorption spectra differences arising from acoustic plasmonic dispersion variations.
• Employing a simplified model to extract nonlocal effects from spectral data.

Main Results:

• Demonstrated that the coupling between GPs and APs is sensitive to acoustic plasmonic dispersion.
• Observed distinct absorption spectra dependent on the consideration of nonlocal responses.
• Showcased the ability to extract nonlocal effects using a simple model.

Conclusions:

• The proposed scheme provides a promising platform for investigating nonlocal effects in metals.
• This approach enables manipulation of nanophotonics through controlled plasmon coupling.
• The study highlights the importance of nonlocal effects in understanding plasmon behavior in nanostructures.