Perrin Bernard is Directeur de Recherche at CNRS and Head of INSP “Institute of NanoSciences in Paris” (UMR 7588 CNRS- Pierre & Marie Curie University). Born in 1951, he obtained his PhD in 1987 on theoretical and experimental studies of phonon-phonon interactions. He worked in several laboratories in Pierre & Marie Curie University : he has been successively « chargé de recherche CNRS » in the “Laboratoire de Recherche Physique”, « Directeur de Recherche CNRS » in the « Laboratoire de Dynamique de la Matière Condensée » then in the « Laboratoire des Milieux Désordonnés et Hétérogènes ». He worked on nonlinear acoustics, phonon interactions and phonons transport in dielectric crystals, molecular crystals and quasi crystals. In 1994, he introduced in Europe «Picosecond Acoustics », which is an optical pump and probe technique allowing generation and detection of very short acoustic pulses and he applied this technique to many different systems and problems: thin films , superlattices, nanostructures and nano-objects but also bulk systems; he has been interested to elastic properties, effects of disorder, interfaces adhesion, phonon lifetimes .More recently he studied formation of acoustic solitons and started works on conception, realization and use of emitters and detectors of coherent acoustic waves in the Terahertz range . He demonstrated successfully that these new devices could be use to propagate such ultra high frequency acoustic waves on large distances and realized direct measurements of terahertz phonons mean paths. He also just started optomechanics studies in the range of tens of GHz.