Oliver Wright speaking on "Tracking surface phonons on phononic crystals", September 13, 2007

Tracking surface phonons on phononic crystals

Periodic elastic structures, or phononic crystals, promise diverse applications in the control of propagating sound. These acoustic metamaterials, with one-, two- or three- dimensional periodicity in their acoustic impedance, possess stop bands where the elastic waves are heavily damped. We track broadband surface phonon wave packets in 1D and 2D microscopic phononic crystals in two dimensions and in real time with an ultrafast optical technique. The eigenmode distribution and the 2D acoustic band structure are obtained from spatiotemporal Fourier transforms of the data up to 1 GHz. We find stop bands at the zone boundaries for both leaky-longitudinal and Rayleigh waves, and show how the structure of individual acoustic eigenmodes in k-space depends on Bloch harmonics and on mode coupling. We also track phonon pulses in phononic crystal waveguides and cavities.

Daniel HISSEL awarded as « Fellow » of the IEEE society
Professor in Electrical Engineering at the University of Franche-Comté and researcher at FEMTO-ST, Daniel Hissel has been awarded as for his work on hydrogen systems.
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March 8, International Women's Day
"Freedom, like Science, and Women's Rights, are fundamental issues for Humanity."

FEMTO-ST chooses to display on this day of March 8 (also charged with the serious news of the war in Ukraine), its commitment to each of these three issues.
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First experimental observation of the roton effect in metamaterials
Experiments conducted jointly by FEMTO-ST and KIT demonstrate the control of forward and backward wave propagation by adjusting the frequency.
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FEMTO-ST partner of the Joint Technology Unit "CAPPLAI"
For the development of sensors to control and optimize the performance of dairy processes.
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Happy new year 2022 !
The Management and all the members of FEMTO-ST wish you a year 2022 full of personal and professional satisfactions
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Safa MERAGHNI receives the PEPITE prize in the regional "Female Initiative " competition
Her project is to create a "Smart Medical Assistant" which is an intelligent medical assistance device on a smartphone designed to help doctors in their diagnosis.
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IEEE ICEMS Conference : Best paper award
Researchers from SHARPAC team/ENERGY department of FEMTO-ST institute received the Best Paper Award at the IEEE International Conference on Electrical Machines and Systems for their work on the influence of electrical conductivity on eddy-current losses in electrical machines.
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Joint laboratories CNRS-Companies 2021
FEMTO-ST and AUREA Technology honored at the LAB COM CNRS event in Paris on November 29 and 30
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Nanorobotics of the future: FEMTO-ST enters the 4th dimension
For the first time, nanorobotic structures have been realized by folding in 3 dimensions a multilayer membrane and proposing their actuation by an electro-thermo mechanical principle.
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Chaos and rogue waves in a supercontinuum laser
In collaboration with the Universities of Tampere, Aston and ICB laboratory, FEMTO-ST researchers have made significant headway in the ongoing effort to understand the ultrafast chaotic nature of lasers, elucidating for the first time their noise-like pulse operation.
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