Mirror‑Induced Field Compression Drives Tunable Strong Exciton–Plasmon Polaritons in WS <sub>2</sub> /h‐BN/Au Heterostructures
Abstract
ABSTRACT Deep‑subwavelength confinement and strong coupling at visible frequencies are central to scalable nanophotonic and quantum technologies. While transition metal dichalcogenides are promising candidates for such confinement, achieving tunable strong coupling often relies on patterned plasmonic nanostructures or chemical modification of the excitonic material. Furthermore, in metal‐coupled systems, the distinct role of metallic mirror‐induced electromagnetic confinement is often experimentally obscured by exciton‐plasmon energy hybridization. Here we introduce a vdW‐integrated, chemically non‐invasive WS 2 /h‐BN/Au heterostructure in which the h‐BN spacer forms a controllable nanogap that tunes image‐charge confinement while preserving the excitonic material. Scattering‑type near‑field microscopy directly maps propagating interference fringes and reveals a collapse of the TM‑polariton wavelength to ∼172 nm under 633‑nm excitation as the spacer is reduced to 5 nm ( λ 0 / λ p ≈3.7, corresponding to ∼71% wavelength reduction), which is one of the highest degrees of optical confinement reported for room‐temperature TMDC polaritons. Full‑wave simulations and transfer‑matrix analysis, aided by boundary‑condition engineering from an ideal conductor to real Au, separate a purely geometric mirror mode from plasmon‑assisted hybridization. This platform establishes a deterministic route to deeply subwavelength field control, offering a scalable architecture for nonlinear optical enhancement and integrated quantum devices.
Article Details
Authors (9)
Xiu‐Qi Shi
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
Jun‐Rong Zheng
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
Zhao‐Dong Meng
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
Yi‐Cheng Xu
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
Li‐Lin Zhu
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
Yong‐Jia Yao
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
Zhi‐Peng Dong
School of Electronic Science and Engineering State Key Laboratory of Physical Chemistry of Solid Surfaces College of Physical Science and Technology Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen University Xiamen China
En‐Ming You
School of Ocean Information Engineering Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent Processing Jimei University Xiamen China
Jun Yi
Department of Chemistry