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TESTING February 23, 2026

Circular V-grooves on single-crystal gold: optical properties and sensing feasibility

Authors

Amos Sospeter Kiyumbi

Abstract

Single-crystal Au(111) microplates provide an ultra-smooth, low-defect platform for reproducible plasmonic nanocavities. Here we realize reflection-mode whispering-gallery metasurfaces comprising periodic arrays of circular V-groove cavities milled into optically thick Au microplates and characterize their visible--near-IR response. The measured spectra exhibit narrow, depth-tunable Fano-like reflectance minima with weak azimuthal dependence, reproduced by quarter-cell finite-element modeling consistent with strong gap-surface-plasmon confinement. For refractometric sensing, simulations yield bulk sensitivities up to $\sim 598$ nm RIU$^{-1}$ and figures of merit up to $\sim 33$ (hexagonal lattice). As a model-based illustration, a functionalized architecture targeting \textit{Plasmodium falciparum} lactate dehydrogenase (PfLDH), a common malaria target of rapid diagnostic tests, gives an estimated limit of detection of $0.016$ nM ($\sim 0.56$ ng mL$^{-1}$) under the adopted noise floor.

Metadata

arXiv ID: 2602.19665
Provider: ARXIV
Primary Category: physics.optics
Published: 2026-02-23
Fetched: 2026-02-24 04:38

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