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Polaritons in two-dimensional (2D) materials provide unique opportunities for controlling light at nanoscales. Tailoring these polaritons via gradient polaritonic surfaces with space-variant response can enable versatile light-matter interaction platforms with advanced functionalities. However, experimental progress has been hampered by the optical losses and poor light confinement of conventionally used artificial nanostructures. Here, we demonstrate natural gradient polaritonic surfaces based on superlattices of solitons—localized structural deformations—in a prototypical moiré system, twisted bilayer graphene on boron nitride. We demonstrate on-off switching and continuous modulation of local polariton-soliton interactions, which results from marked modifications of topological and conventional soliton states through variation of local strain direction. Furthermore, we reveal the capability of these structures to spatially modify the near-field profile, phase, and propagation direction of polaritons in record-small footprints, enabling generation and electrical switching of directional polaritons. Our findings open up new avenues toward nanoscale manipulation of light-matter interactions and spatial polariton engineering through gradient moiré superlattices.
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This content will become publicly available on January 13, 2026
Significantly enhanced near-field coupling via tip engineering
The ability to significantly enhance near-field coupling between light and matter at the nanoscale is crucial for advancing the fields of nanophotonics and nanopolariotonics. However, conventional probes face challenges in achieving optimal light–matter interaction. In this study, we propose a novel, to the best of our knowledge, simulation-based strategy that leverages tip engineering to dramatically amplify the scattering field through tailored double-layer geometries. By employing a core-shell structure with a thin shell layer optimized for specific dielectric permittivity and effective polarizability, we demonstrate a near-field enhancement of up to 10 times compared to conventional probes. Our findings highlight exciting new possibilities for optimizing near-field interactions through probe designs with customized resonances, paving the way for substantially improved nano-optical sensing, imaging, and detection.
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- Award ID(s):
- 2145074
- PAR ID:
- 10566169
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Letters
- Volume:
- 50
- Issue:
- 2
- ISSN:
- 0146-9592; OPLEDP
- Format(s):
- Medium: X Size: Article No. 590
- Size(s):
- Article No. 590
- Sponsoring Org:
- National Science Foundation
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