arXiv subjects

Yu-Chen Wei

Publications and source records attributed to Yu-Chen Wei.

6 recordsLinked to original sources

arXiv2026

Dispersion Control of Chiral Exciton-Polariton Transport with Dielectric Metasurfaces

Exciton-polaritons provide a powerful platform for manipulating hybrid light-matter states with low effective masses and strong nonlinearities. Introducing chirality into these quasiparticles enables selective control over their spin and propagation, opening new opportunities for chiral transport and spin-selective polaritonic devices. We exploit the strong chiral light-matter coupling in silicon metasurfaces composed of tilted nanorod dimers to demonstrate selective transport of organic chiral exciton-polaritons. The metasurface supports surface lattice resonances and quasi-bound states in the continuum that simultaneously provide high photonic confinement and extrinsic chirality, giving rise to chiral exciton-polaritons in the achiral molecules. These exciton-polaritons exhibit a large magnitude of the dissymmetry factor, reaching a value of 0.93. Using photoluminescence Fourier microscopy and real-space imaging, we show that chiral exciton-polaritons propagate over distances exceeding 50 um without significant degradation of their dissymmetry, with characteristic propagation lengths of approximately 6-13 um. These propagation lengths correspond to an enhancement of 3 orders of magnitude compared to bare excitons. This work constitutes the first demonstration of enhanced and selective chiral transport of organic exciton-polaritons, driven by strong light-matter coupling, in achiral metasurfaces, paving the way for spin-selective polaritonic technologies using simple metasurfaces.

physics.optics↗

arXiv2025

Robust Circularly Polarized Luminescence via Quasi-Bound States in the Continuum in Intrinsic Chiral Silicon Metasurfaces

We demonstrate a circularly polarized photoluminescence emission, with dissymmetry factors $g_\mathrm{PL}$ over 0.1, from achiral organic dye molecules by leveraging quasi-bound states in the continuum (quasi-BICs) and surface lattice resonances (SLRs) in intrinsic silicon chiral metasurfaces. We find that the $g_\mathrm{PL}$ associated with the quasi-BIC mode remains robust against variations in emission angle and dye thickness owing to its strong lateral field confinement. In contrast, the $g_\mathrm{PL}$ of the SLR mode exhibits sign inversion depending on the emission energy and dye layer thickness. The experimental results are supported by mode decomposition analysis, helicity density analysis, and near-field spatial distribution of the electric field. These findings illustrate the relevance of the emitter's layer thickness in optimizing the emission of circularly polarized light. They also elaborate on the robustness of chiral quasi-BICs, offering insights into chiral light-matter interactions and advancing the design of circularly polarized light-emitting devices.

physics.optics↗

arXiv2025

Enhanced Delayed Fluorescence in Non-Local Metasurfaces: The Role of Electronic Strong Coupling

Strong light-matter coupling has garnered significant attention for its potential to optimize optoelectronic responses. In this study, we designed open cavities featuring non-local metasurfaces composed of aluminum nanoparticle arrays. The surface lattice resonances in these metasurfaces exhibit electronic strong coupling with the boron difluoride curcuminoid derivative, known for its highly efficient thermally activated delayed f luorescence in the near-infrared. Our results show that delayed fluorescence induced by triplet-triplet annihilation can be enhanced by a factor of 2.0-2.6 in metasurfaces that are either tuned or detuned to the molecular electronic transition. We demonstrate that delayed fluorescence enhancements in these systems primarily stem from increased absorption in the organic layer caused by the nanoparticle array, while strong coupling has negligible effects on reverse intersystem crossing rates, aligning with previous studies. We support these findings with finite-difference-time-domain simulations. This study elucidates how light-matter interactions affect delayed fluorescence, highlighting the potential applications in optoelectronic devices.

physics.optics↗

arXiv2024

Polaritonic Chemistry Enabled by Non-Local Metasurfaces

Vibrational strong coupling can modify chemical reaction pathways in unconventional ways. Thus far, Fabry-Perot cavities formed by pairs of facing mirrors have been mostly utilized to achieve vibrational strong coupling. In this study, we demonstrate the application of plasmonic microparticle arrays defining non-local metasurfaces that can sustain surface lattice resonances as a novel tool to enable chemical reactions under vibrational strong coupling. We show that the solvolysis kinetics of \textit{para}-nitrophenyl acetate can be accelerated by a factor of 2.7 by strong coupling to the carbonyl bond of the solvent and the solute with a surface lattice resonance. Our work introduces a new platform to investigate and control polaritonic chemical reactions. In contrast to Fabry-Perot cavities, metasurfaces define open optical cavities with single surfaces, which removes alignment hurdles, facilitating polaritonic chemistry across large areas.

physics.chem-ph↗

arXiv2023

Wide-Dynamic-Range Control of Quantum-Electrodynamic Electron Transfer Reactions in the Weak Coupling Regime

Catalyzing reactions effectively by vacuum fluctuations of electromagnetic fields is a significant challenge within the realm of chemistry. Different from most studies based on vibrational strong coupling, we introduce an innovative catalytic mechanism driven by weakly coupled polaritonic fields. Through the amalgamation of macroscopic quantum electrodynamics (QED) principles with Marcus electron transfer (ET) theory, our results reveal that ET reaction rates can be precisely modulated across a wide dynamic range by controlling the size and structure of nanocavities. Comparing to QED-driven radiative ET rates in free space, plasmonic cavities induce substantial rate enhancements spanning from orders of magnitude ranging from 10^3-fold to 10^1-fold. By contrast, Fabry-Perot cavities engender rate suppression spanning from 10^{-2}-fold to 10^{-1}-fold. This work overcomes the necessity of using strong light-matter interactions in QED chemistry, opening up a new era of manipulating QED-based chemical reactions in a wide dynamic range.

physics.chem-ph↗

arXiv2022

Polaritonic Huang-Rhys Factor: Basic Concepts and Quantifying Light-Matter Interaction in Medium

Huang-Rhys (HR) factor, a dimensionless factor that characterizes electron-phonon coupling, has been extensively employed to investigate material properties in various fields. In the same spirit, we present a quantity called polaritonic HR factor to quantitatively describe the effects of (i) light-matter coupling induced by permanent dipoles and (ii) dipole self-energy. The former can be viewed as polaritonic displacements, while the latter is associated with the electronic coupling shift. In the framework of macroscopic quantum electrodynamics, the polaritonic HR factor, coupling shift, and modified light-matter coupling strength in an arbitrary dielectric environment can be evaluated without free parameters, whose magnitudes are in good agreement with the previous experimental results. In addition, polaritonic progression developed in our theory indicates that large polaritonic HR factors can result in light-matter decoupling, multipolariton formation, and non-radiative transition. We believe that this study provides a useful perspective to understand and quantify light-matter interaction in medium.

physics.chem-ph↗