A detailed characterization of plasmon modes is important not only for a deeper understanding of plasmons but also for their practical applications. In this study, we investigated the three-dimensional near-field characteristics of high-order plasmon modes excited in a gold hexagonal nanoplate. From the near-field spectroscopic images, we found that both in-plane and out-of-plane plasmon modes observed near 900 nm were spectrally and spatially overlapped. We performed three-dimensional near-field measurement to reveal the optical characteristics of the overlapped modes in detail. We found that the steric near-field distribution near the nanoplate strongly depended on the plasmon mode, and the out-of-plane mode confines electromagnetic fields more tightly than the in-plane mode. We also found that the in-plane mode was dominantly visualized as the probe tip-sample distance increased. These findings demonstrate that the three-dimensional near-field technique enables selective visualization of a single plasmon mode even if multiple modes are spatially and spectrally overlapped.
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http://dx.doi.org/10.1021/acs.jpclett.8b03578 | DOI Listing |
Nano Lett
January 2025
NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
Metal nanocrystals synthesized in achiral environments usually exhibit no chiroptical effects. However, by placing nominally achiral nanocrystals 1.3 nm above gold films, we find giant chiroptical effects, reaching anisotropy factors as high as ≈ 0.
View Article and Find Full Text PDFNanoscale Adv
January 2025
School of Electrical Engineering and Computer Science, University of Ottawa Ottawa Ontario K1N 6N5 Canada
Interference of surface plasmons has been widely utilized in optical metrology for applications such as high-precision sensing. In this paper, we introduce a surface plasmon interferometer with the potential to be arranged in arrays for parallel multiplexing applications. The interferometer features two grating couplers that excite surface plasmon polariton (SPP) waves traveling along a gold-air interface before converging at a gold nanoslit where they interfere.
View Article and Find Full Text PDFACS Nano
January 2025
Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Controlling the light emitted by individual molecules is instrumental to a number of advanced nanotechnologies ranging from super-resolution bioimaging and molecular sensing to quantum nanophotonics. Molecular emission can be tailored by modifying the local photonic environment, for example, by precisely placing a single molecule inside a plasmonic nanocavity with the help of DNA origami. Here, using this scalable approach, we show that commercial fluorophores may experience giant Purcell factors and Lamb shifts, reaching values on par with those recently reported in scanning tip experiments.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Division of Computer, Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
We propose and demonstrate a data-driven plasmonic metascreen that efficiently absorbs incident light over a wide spectral range in an ultra-thin silicon film. By embedding a double-nanoring silver array within a 20 nm ultrathin amorphous silicon (a-Si) layer, we achieve a significant enhancement of light absorption. This enhancement arises from the interaction between the resonant cavity modes and localized plasmonic modes, requiring precise tuning of plasmon resonances to match the absorption region of the silicon active layer.
View Article and Find Full Text PDFACS Nano
January 2025
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, PR China.
The ever-growing interest in MXenes has been driven by their distinct electrical, thermal, mechanical, and optical properties. In this context, further revealing their physicochemical attributes remains the key frontier of MXene materials. Herein, we report the anisotropic localized surface plasmon resonance (LSPR) features in TiCT MXene as well as site-selective photocatalysis enabled by the photophysical anisotropy.
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