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Low-Loss

Scientific highlights

Tailored nanoscale plasmon-enhanced vibrational electron spectroscopy

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Atomic vibrations and phonons are an excellent source of information on nanomaterials that we can access through a variety of methods including Raman Scattering, infrared spectroscopy, and electron energy-loss spectroscopy (EELS). In the presence of a plasmon local field, vibrations are strongly modified, and in particular, their dipolar strengths are highly enhanced, thus rendering Raman scattering and infrared spectroscopy extremely sensitive techniques. Here, we experimentally demonstrate that the interacion between a relativistic electron and vibrational modes in nanostructures is fundamentally modified in the presence of plasmons. We finely tune the energy of surface plasmons in metallic nanowires in the vicinity of hexagonal boron nitride, making it possible to monitor and disentangle both strong phonon-plasmon coupling and plasmon-driven phonon enhancement at the nanometer scale. Due to the near-field character of the electron beam-phonon interaction, optically-inactive phonon modes are also observed. Read more »

Optical gap and optically active intragap defects in cubic BN

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Studies on the optical properties of cubic BN are generally hindered by the very high density of crystal defects. Thus, the precise value of its optical gap is still debated, with large discrepancies between reported theoretical and experimental estimated values. In this study we addressed open questions of the cubic BN optics by employing high spatially resolved spectroscopy techniques to the highest-quality samples available and combining these observations with state-of-the-art quasiparticle calculations.

Phys. Rev. B 98, 094106 (2018)

Publications

Tararan, A., et al. Optical gap and optically active intragap defects in cubic BN. Physical Review B 982121, (2018). Download: PhysRevB.98.094106.pdf (2.16 MB)
Campos, A., et al. Plasmonic Breathing and Edge Modes in Aluminum Nanotriangles. ACS Photonics (2017).doi:10.1021/acsphotonics.7b00204 Download: Campos2017.pdf (5.45 MB)
Kociak, M. & Zagonel, L.F. Cathodoluminescence in the scanning transmission electron microscope. Ultramicroscopy 176, 112-131 (2017). Download: STEMCL_8.pdf (2.43 MB)
Kociak, M. & Stéphan, O. Mapping plasmons at the nanometer scale in an electron microscope. Chemical Society Reviews (2014).doi:10.1039/c3cs60478k Download: Chem. Soc. Rev. 2014 Kociak.pdf (2.86 MB)
Rodríguez-González, B., et al. Surface Plasmon Mapping of Dumbbell-Shaped Gold Nanorods: The Effect of Silver Coating. Langmuir 120410144721001 (2012).doi:10.1021/la300269n Download: la300269n.pdf (4.19 MB)
Mazzucco, S., et al. Spatially resolved measurements of plasmonic eigenstates in complex-shaped, asymmetric nanoparticles: gold nanostars. The European Physical Journal Applied Physics 54, 33512 (2011). Download: Eur. Phys. J. Appl. Phys. 2011 Mazzucco.pdf (3 MB)
Boudarham, G., et al. Spectral Imaging of Individual Split-Ring Resonators. Physical Review Letters 105, 255501 (2010). Download: Phys. Rev. Lett. 2010 Boudarham.pdf (567.25 KB)
Nelayah, J., et al. Two-Dimensional Quasistatic Stationary Short Range Surface Plasmons in Flat Nanoprisms. Nano Letters 10, 902–907 (2010). Download: Nano Lett. 2010 Nelayah.pdf (2.58 MB)
Arenal, R., et al. Optical gap measurements on individual boron nitride nanotubes by electron energy loss spectroscopy. Microscopy And Microanalysis 14, 274–282 (2008).
Nelayah, J., et al. Mapping surface plasmons on a single metallic nanoparticle. Nature Physics 3, 348–353 (2007). Download: Nat Phys 2007 Nelayah.pdf (676.34 KB)
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