Gradient polaritonic surface with space-variant switchable light-matter interactions in 2D moiré superlattices

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanophotonics

Background:

• Two-dimensional (2D) materials offer unique platforms for nanoscale light control via polaritons.
• Artificial nanostructures face limitations like optical losses and poor light confinement for polariton manipulation.
• Gradient polaritonic surfaces with space-variant responses are desired for advanced light-matter interactions.

Purpose of the Study:

• To demonstrate natural gradient polaritonic surfaces for enhanced light-matter interactions.
• To overcome limitations of artificial nanostructures in polariton control.
• To enable nanoscale manipulation and spatial engineering of polaritons.

Main Methods:

• Utilized moiré superlattices in twisted bilayer graphene on boron nitride.
• Investigated superlattices of solitons (localized structural deformations).
• Analyzed modifications of topological and conventional soliton states via local strain direction variation.

Main Results:

• Demonstrated on-off switching and continuous modulation of local polariton-soliton interactions.
• Showcased spatial modification of polariton near-field profile, phase, and propagation direction.
• Achieved generation and electrical switching of directional polaritons in record-small footprints.

Conclusions:

• Natural gradient polaritonic surfaces based on moiré superlattices offer a novel approach for nanoscale light control.
• These surfaces enable precise manipulation of polariton properties and light-matter interactions.
• The findings open new avenues for spatial polariton engineering and advanced photonic devices.