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.

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.
Read more
Joint laboratories CNRS-Companies 2021
FEMTO-ST and AUREA Technology honored at the LAB COM CNRS event in Paris on November 29 and 30
Read more
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.
Read more
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.
Read more
Julio Andrés Iglesias Martínez receives the Best Student Award at IEEE Ultrasonic Symposium
His work consists in achieving three-dimensional phononic crystals at the micro-scale with record band-gap width.
Read more
Lessons on textile history and fibre durability from a 4,000-year-old Egyptian flax yarn
Published in the journal Nature Plants, work involving FEMTO-ST scientists is helping to propose ever more efficient and resistant materials based on flax fibers.
Read more
Programmable matter: world record attempt
A FEMTO-ST research team is trying to get the record for the largest number of autonomous light blocks assembled in a structure approved by the "Guiness World Record".
Read more
Rodolphe Boudot receives the 2020 EFTF Young Scientist Award
The IEEE EFTF-IFCS 2021 is a joint conference of the European Frequency and Time Forum and the IEEE International Frequency Control Symposium. The 2021 joint conference, originally planned for Paris in April, has been converted to a virtual conference from 7th to 17th July, 2021
Read more
Giacomo Clementi, grand prize i-PhD
For his work on Lithium Niobate (LiNbO3), which has led to the design of original and efficient devices for the recovery of vibratory energy by the piezoelectric effect, in particular for connected objects.
Read more
Understanding energy transfers during photosynthesis
Using three pigments manipulated by scanning tunneling microscopy, researchers from IPCMS and FEMTO-ST are studying energy transfers between molecules to gain a finer understanding of the photosynthesis mechanism in plants. This work is published in Nature Chemistry.
Read more