Plasmonic nanocavities are able to engineer and confine electromagnetic fields to subwavelength volumes. In the past decade, they have enabled a large set of applications, in particular for sensing, optical trapping, and the investigation of physical and chemical phenomena at a few or single-molecule levels. This extreme sensitivity is possible thanks to the highly confined local field intensity enhancement, which depends on the geometry of plasmonic nanocavities. Indeed, suitably designed structures providing engineered local optical fields lead to enhanced optical sensing based on different phenomena such as surface enhanced Raman scattering, fluorescence, and Förster resonance energy transfer. In this mini-review, we illustrate the most recent results on plasmonic nanocavities, with specific emphasis on the detection of single molecules.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9418431 | PMC |
http://dx.doi.org/10.1039/d0na00715c | DOI Listing |
Nanophotonics
January 2025
Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Sum-frequency generation (SFG) enables the coherent upconversion of electromagnetic signals and plays a significant role in mid-infrared vibrational spectroscopy for molecular analysis. Recent research indicates that plasmonic nanocavities, which confine light to extremely small volumes, can facilitate the detection of vibrational SFG signals from individual molecules by leveraging surface-enhanced Raman scattering combined with mid-infrared laser excitation. In this article, we compute the degree of second order coherence ( (0)) of the upconverted mid-infrared field under realistic parameters and accounting for the anharmonic potential that characterizes vibrational modes of individual molecules.
View Article and Find Full Text PDFNat Chem
January 2025
Department of Chemistry, University of California Irvine, Irvine, CA, USA.
Controlling reaction outcomes through external influences is a central goal in chemistry. Vibrational coupling between molecular vibrations and cavity modes is rapidly emerging as a distinct strategy compared with conventional thermochemical and photochemical methods; however, insight into the fundamental mechanisms remains limited. Here we investigate how vibrational weak and strong coupling in plasmonic nanocavities modifies the thermal dehydration of copper sulfate pentahydrate.
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 PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Energy, Xiamen University, Xiamen 361005, China.
Since 1997, driven by advancements in nanoscience, single-molecule plasmon-enhanced Raman spectroscopy (SM-PERS) has developed into a powerful technique for ultrasensitive trace analysis through fingerprint vibrational chemical information. The nanocavity between the coupled plasmonic nanostructures, offering an exceptionally high Raman signal enhancement factor (i.e.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Materials Science and Engineering, Centre for Functional Photonics, and Hong Kong Branch of National Precious Metals Material Engineering Research Centre, City University of Hong Kong, Hong Kong S.A.R., 999077, China.
The emission efficiency of interlayer excitons (IEs) in twisted 2D heterostructures has long suffered from momentum mismatch, limiting their applications in ultracompact excitonic devices. Here, we report strong room-temperature emission of the momentum-forbidden IEs in a 30°-twisted MoS/WS heterobilayer. Utilizing the Purcell effect of a compact plasmonic nanocavity boosts the IE emission intensity in the cavity by over 2 orders of magnitude.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!