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Self-hybridization within non-Hermitian localized plasmonic systems

Figure 1 : Left : Energy variation of two modes of silver nano-daggers as a function of the vertical arm length L. A clear anti-

In a recent paper published in Nature Physics, we show that electron energy loss spectroscopy in a scanning transmission electron microscope reveals the possibility for two eigenmodes from the same nanoparticle to hybridize – a physical effect that cannot be observed in day-to-day (Hermitian) linear physics Read more »

Vibrational Surface Electron-Energy-Loss Spectroscopy Probes Confined Surface-Phonon Modes

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Phonons are vibration waves that propagate in solids. Their study and quantification is fundamental for understanding many material properties, from superconductivity to thermoelectricity. Numerous techniques have been developed for studying phonons, such as high-resolution electron-energy-loss spectroscopy (HREELS), in which electrons are sent toward an object of interest, and the energy of the phonons is deduced from that lost by the electrons. Recently, HREELS has been pushed to the nanometer scale. With the success of these experiments, researchers now want to determine what types of phonons are being measured and how to rationalize some of the observations. A similar problem once arose in HREELS experiments on electronic waves known as plasmons, experiments that were interpreted at the time using analogies with phonons. In a recent paper published in PRX, we show that, in a reversal of traditional analogies, current phonon experiments can now be interpreted using modern concepts for plasmons. Read more »

Publications

Lourenço-Martins, H., Das, P., Tizei, L.H.G., Weil, R. & Kociak, M. Self-hybridization within non-Hermitian localized plasmonic systems. Nature Physics 89, (2018). Download: LM2018.pdf (3.41 MB)
Guzzinati, G., et al. Probing the symmetry of the potential of localized surface plasmon resonances with phase-shaped electron beams. Nature Communications 14999 (2017).doi:10.1038/ncomms14999 Download: Nature Communications 2017 eacute.pdf (1.55 MB)
Kociak, M., et al. Seeing and measuring in colours: Electron microscopy and spectroscopies applied to nano-optics. Comptes Rendus Physique 15, 158 - 175 (2014). Download: 1-s2.0-S1631070513001515-main.pdf (2.66 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)
de Abajo, F.J.G., Asenjo-Garcia, A. & Kociak, M. Multiphoton Absorption and Emission by Interaction of Swift Electrons with Evanescent Light Fields. Nano Letters 10, 1859–1863 (2010).
de Abajo, F.J.G. & Kociak, M. Probing the Photonic Local Density of States with Electron Energy Loss Spectroscopy. Physical Review Letters 100, 106804 (2008). Download: Phys. Rev. Lett. 2008 García de Abajo.pdf (540.82 KB)
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