0000000000312418

AUTHOR

E. H. El Boudouti

showing 3 related works from this author

Defect-controlled hypersound propagation in hybrid superlattices

2013

We employ spontaneous Brillouin light scattering spectroscopy and detailed theoretical calculations to reveal and identify elastic excitations inside the band gap of hypersonic hybrid superlattices. Surface and cavity modes, their strength and anticrossing are unambiguously documented and fully controlled by layer thickness, elasticity, and sequence design. This new soft matter based superlattice platform allows facile engineering of the density of states and opens new pathways to tunable phoxonic crystals.

[PHYS]Physics [physics]Hypersonic speedMaterials scienceCondensed matter physicsBand gapSuperlatticeGeneral Physics and Astronomy02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesLayer thicknessBrillouin zone0103 physical sciencesDensity of statesSoft matterElasticity (economics)010306 general physics0210 nano-technology
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Direction-dependent elastic properties and phononic behavior of PMMA/BaTiO 3 nanocomposite thin films

2017

Determination of the anisotropic mechanical properties of nanostructured hybrid films is of great importance to improve fabrication and to enable reliable utility. Here, we employ spontaneous Brillouin light spectroscopy to record the phononic dispersion relation along the two symmetry directions in a supported PMMA (poly(methylmethacrylate))-BaTiO3 hybrid superlattice (SL) with a lattice constant of about 140 nm. Several dispersive elastic modes are resolved for in-plane wave propagation, whereas along the periodicity direction the SL opens a wide propagation stop band for hypersonic phonons and near UV photons both centered at about 280 nm. A thorough theoretical analysis based on the fin…

NanocompositeMaterials scienceCondensed matter physicsWave propagationPhononbusiness.industrySuperlatticeGeneral Physics and Astronomy02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesBrillouin zoneCondensed Matter::Materials ScienceOpticsDispersion relation0103 physical sciencesPhysical and Theoretical ChemistryPhase velocity010306 general physics0210 nano-technologyAnisotropybusinessThe Journal of Chemical Physics
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Engineering the hypersonic phononic band gap of hybrid Bragg stacks.

2012

We report on the full control of phononic band diagrams for periodic stacks of alternating layers of poly(methyl methacrylate) and porous silica combining Brillouin light scattering spectroscopy and theoretical calculations. These structures exhibit large and robust on-axis band gaps determined by the longitudinal sound velocities, densities, and spacing ratio. A facile tuning of the gap width is realized at oblique incidence utilizing the vector nature of the elastic wave propagation. Off-axis propagation involves sagittal waves in the individual layers, allowing access to shear moduli at nanoscale. The full theoretical description discerns the most important features of the hypersonic one…

Hypersonic speedMaterials scienceLightBand gapSuperlatticeBioengineering02 engineering and technology01 natural sciencesOpticsDispersion relation0103 physical sciencesScattering RadiationGeneral Materials ScienceComputer SimulationParticle Size010306 general physicsNanoscopic scaleBrillouin SpectroscopyCondensed matter physicsbusiness.industryMechanical EngineeringGeneral Chemistry021001 nanoscience & nanotechnologyCondensed Matter PhysicsNanostructuresBrillouin zoneShear (sheet metal)RefractometryModels Chemical0210 nano-technologybusinessNano letters
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