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8 results on '"Charbonnier, Romain"'

1. Assessing the Performance of a 60-GHz Dense Small-Cell Network Deployment from Ray-Based Simulations

Author

Corre, Yoann, Charbonnier, Romain, Aslam, Mohammed Zahid, and Lostanlen, Yves

Subjects
Computer Science - Networking and Internet Architecture
Abstract

Future dense small-cell networks are one key 5G candidates to offer outdoor high access data rates, especially in millimeter wave (mmWave) frequency bands. At those frequencies, the free space propagation loss and shadowing (from buildings, vegetation or any kind of obstacles) are far stronger than in the traditional radio cellular spectrum. Therefore, the cell range is expected to be limited to 50 - 100 meters, and directive high gain antennas are required at least for the base stations. This paper investigates the kind of topology that is required to serve a suburban area with a small-cell network operating at 60 GHz and equipped with beam-steering antennas. A real environment is considered to introduce practical deployment and propagation constraints. The analysis relies on Monte-Carlo system simulations with non-full buffer, and ray-based predictions. The ray-tracing techniques are today identified as a relevant solution to capture the main channel properties impacting the beam-steering performance (angular dispersion, inter-link correlation); and the one involved in the present study was specifically enhanced to deal with detailed vegetation modeling. In addition to the user outage, the paper evaluates the evolution of the inter-cell interference along with the user density, and investigates the network behavior in case of local strong obstructions., Comment: IEEE 21st International Workshop on Computer Aided Modelling and Design of Communication Links and Networks (CAMAD), October 2016

Published
2016

7. In SituObservation of Coulomb Fission of Individual Plasmonic Nanoparticles

Author

Voss, Jonathan M., Olshin, Pavel K., Charbonnier, Romain, Drabbels, Marcel, and Lorenz, Ulrich J.

Abstract

Reshaping plasmonic nanoparticles with laser pulses has been extensively researched as a tool for tuning their properties. However, in the absence of direct observations of the processes involved, important mechanistic details have remained elusive. Here, we present an in situelectron microscopy study of one such process that involves Coulomb fission of plasmonic nanoparticles under femtosecond laser irradiation. We observe that gold nanoparticles encapsulated in a silica shell fission by emitting progeny droplets comprised of about 10–500 atoms, with ejection preferentially occurring along the laser polarization direction. Under continued irradiation, the emitted droplets coalesce into a second core within the silica shell, and the system evolves into a dual-core particle. Our findings are consistent with a mechanism in which electrons are preferentially emitted from the gold core along the laser polarization direction. The resulting anisotropic charge distribution in the silica shell then determines the direction in which progeny droplets are ejected. In addition to yielding insights into the mechanism of Coulomb fission in plasmonic nanoparticles, our experiments point toward a facile method for forming surfaces decorated with aligned dual-gold-core silica shell particles.

Published
2019
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8. In Situ Observation of Coulomb Fission of Individual Plasmonic Nanoparticles

Author

Voss, Jonathan M., Olshin, Pavel K., Charbonnier, Romain, Drabbels, Marcel, and Lorenz, Ulrich J.

Subjects
single-particle observation, gold-core silica shell particles, nanoparticle reshaping, Physics::Atomic and Molecular Clusters, Physics::Optics, Coulomb fission, in situ transmission electron microscopy, plasmonic nanoparticles
Abstract

Reshaping plasmonic nanoparticles with laser pulses has been extensively researched as a tool for tuning their properties. However, in the absence of direct observations of the processes involved, important mechanistic details have remained elusive. Here, we present an in situ electron microscopy study of one such process that involves Coulomb fission of plasmonic nanoparticles under femtosecond laser irradiation. We observe that gold nanoparticles encapsulated in a silica shell fission by emitting progeny droplets comprised of about 10–500 atoms, with ejection preferentially occurring along the laser polarization direction. Under continued irradiation, the emitted droplets coalesce into a second core within the silica shell, and the system evolves into a dual-core particle. Our findings are consistent with a mechanism in which electrons are preferentially emitted from the gold core along the laser polarization direction. The resulting anisotropic charge distribution in the silica shell then determines the direction in which progeny droplets are ejected. In addition to yielding insights into the mechanism of Coulomb fission in plasmonic nanoparticles, our experiments point toward a facile method for forming surfaces decorated with aligned dual-gold-core silica shell particles.

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