Probing the ultimate plasmon confinement limits with a van der Waals heterostructure

Area of Science:

• Plasmonics
• Nanophotonics
• Condensed Matter Physics

Background:

• Confining light to nanoscale dimensions is crucial for microscopy, sensing, and lasers.
• Metal plasmonics face a trade-off between light confinement and optical losses due to Landau damping.
• Graphene-based heterostructures offer potential solutions to overcome plasmonic limitations.

Purpose of the Study:

• To demonstrate plasmon confinement beyond conventional limits using a novel heterostructure.
• To overcome the trade-off between optical field confinement and losses in plasmonics.
• To explore new regimes of light-matter interactions at the atomic scale.

Main Methods:

• Fabrication of a graphene-insulator-metal heterostructure.
• Far-field optical excitation of plasmon modes.
• Utilizing an atomically thin hexagonal boron nitride dielectric spacer.
• Theoretical modeling incorporating nonlocal optical response of graphene and metals.

Main Results:

• Achieved plasmon confinement down to the atomic length scale.
• Demonstrated overcoming the confinement-loss trade-off inherent in traditional metal plasmonics.
• Successfully excited ultraconfined plasmonic modes via far-field illumination.

Conclusions:

• The graphene-insulator-metal heterostructure enables unprecedented plasmon confinement.
• Atomically thin dielectric spacers are key to achieving ultimate plasmonic limits.
• This work opens avenues for ultrastrong light-matter interactions and novel nanoscale devices.