Séminaire

Mardi 10 Décembre 2019 à 11h00.

Bridging the gap between phononics and biology: from man-made to bio- derived ultrasonic metamaterials

''Phononic crystals and locally resonant metamaterials, have been extensively studied due to their ability to enable novel effective properties that arise from their structural periodicity and internal resonances. They already show promising applications across multiple length scales: from seismic wave filtering, to acoustic cloaking, high quality factor opto-mechanical devices, and improved thermoelectric systems. Despite their numerous attractive applications, current man-made phononic materials still suffer from drawbacks that hinder their commercialization and industrial fabrication. For instance, challenges remain with respect to constructing large quantities of discrete, periodic and resonant elements at the micro and nanoscales for application in the MHz to GHz regime. In this work, we present two distinct classes of phononic materials for manipulation of sub-GHz acoustic waves. First, we study the interaction of surface and guided acoustic waves with contact-based dynamics of inorganic microscale colloidal crystals, and reveal dispersion curves characteristic of locally resonant metamaterials. We show the ability to tune the resonant frequency of our self-assembled metamaterial, by up to 250%, via microlensing-enabled modification of the microsphere nanocontact features. Second, we demonstrate that biological composites in the form of micron-thick decellularized onion cell scaffolds behave as an organic phononic material, with the presence of sub-GHz anisotropic band gaps in select frequency ranges. In addition, we reveal the features of these gaps can be phenotypically tuned. Our findings open new avenues to engineer advanced and sustainable phononic materials at ultrasonic frequencies, with future applications ranging from optomechanics, acousto-plasmonics to lab-on-a-chip biosensors.''