Electron Energy Loss Spectroscopy in Plasmonic Nanostructures

Electron energy loss spectroscopy (EELS) has emerged as a cornerstone technique for probing the optical and electronic behaviour of plasmonic nanostructures at nanometre resolution. By analysing the energy lost by a focused electron beam as it traverses or skims a metallic nanoparticle, EELS maps out the excitation of collective oscillations of conduction electrons—localized surface plasmons—with sub-nanometre precision. This capability has transformed our understanding of plasmonic eigenmodes, enabling direct visualisation of mode distribution, coupling phenomena, and energy dispersion in individual nanorods, nanodisks and more complex architectures. Beyond imaging, recent advances have established EELS as a quantitative tool for reconstructing the photonic local density of states in three dimensions, facilitating the design of nanostructures for sensing, optoelectronics and quantum light–matter interfaces. Interfacing EELS with complementary approaches—such as cathodoluminescence, electron tomography and numerical simulations—has deepened insight into substrate effects, mode hybridisation and environmental shifts. As fabrication methods evolve and spectral resolution improves, EELS continues to drive innovations in chiral sensing, active tuning of nanometre-scale optical elements and understanding of vibrational as well as plasmonic excitations.

Research from Nature Portfolio

Comparative fabrication studies have employed EELS to assess the plasmonic quality of gold antennas produced by electron beam lithography versus focused ion beam milling. These analyses reveal that antennas fabricated by electron beam lithography exhibit sharper resonance peaks and stronger field confinement, attributable to superior structural homogeneity and reduced contamination. A seminal study on dispersion relations demonstrated that surface and edge plasmons in silver nanodisks, nanorods and extended films obey simple scaling rules: modes of differing dimensionality can be mapped onto one another by geometric scaling, unifying their dispersion behaviour. In a further advance, three-dimensional tomography based on EELS images and electron-tomography morphology has enabled direct reconstruction of the local photonic density of states around complex nanoparticle assemblies. This approach resolves sub-wavelength hotspots and quantifies how coupling between adjacent particles or surface roughness features enhances light–matter interactions.

Electron Energy Loss Spectroscopy in Plasmonic Nanostructures publication trend

The graph below shows the total number of articles in electron energy loss spectroscopy in plasmonic nanostructures across all publications each year (not limited to Nature Index journals).

Technical terms

Electron Energy Loss Spectroscopy (EELS): Technique measuring the energy lost by electrons interacting with a specimen, revealing plasmon and phonon excitations.

Localized Surface Plasmons (LSPs): Collective oscillations of conduction electrons confined to metallic nanostructure surfaces, responsible for strong optical resonances.

Photonic Local Density of States (LDOS): Spectrum of available electromagnetic modes at a point, determining emission and absorption rates near nanostructures.

Plasmonic Eigenmodes: Characteristic field distributions and resonance energies supported by a plasmonic structure under electron or optical excitation.

Babinet’s Principle: Optical duality stating that complementary structures (particle versus aperture) exhibit related plasmonic resonances, enabling paired sensing designs.

References

1. Electron Beam Induced Circularly Polarized Light Emission of Chiral Gold Nanohelices. ACS Nano (2023).
2. Plasmonic Characterization of 3D Printable Metal–Polymer Nanocomposites. ACS Materials Au (2024).
3. Plasmonic sensing using Babinet’s principle. Nanophotonics (2023).
4. Comparative study of plasmonic antennas fabricated by electron beam and focused ion beam lithography. Scientific Reports (2018).
5. Universal dispersion of surface plasmons in flat nanostructures. Nature Communications (2014).
6. Tomographic imaging of the photonic environment of plasmonic nanoparticles. Nature Communications (2017).
7. Vibrational Surface Electron-Energy-Loss Spectroscopy Probes Confined Surface-Phonon Modes. Physical Review X (2017).
8. Full Three-Dimensonal Reconstruction of the Dyadic Green Tensor from Electron Energy Loss Spectroscopy of Plasmonic Nanoparticles. ACS Photonics (2015).