Departamento de Física da UFPE promove Seminário de Óptica dia 25
O palestrante será o professor Fabrice Vallee, da Universidade de Lyon
Na próxima terça-feira (25) acontecerá o Seminário de Óptica sobre o tema “Time-resolved optical investigation of the acoustic response of metal nanoparticles: from macro to nano-size mechanical resonators”. O evento começará às 14h, no auditório do Departamento de Física da UFPE, e será apresentado pelo professor Fabrice Vallee, da Universidade de Lyon.
Controlling and modeling the mechanical response of nanoscale systems is of central interest for many technological applications. In this size range, breaking of translational invariance leads to appearance of discrete acoustic modes that find application in different domains and also rule many fundamental properties of nano-materials. The acoustic mode frequencies of nano-objects down to the one nanometer size are well described in the framework of the elasticity model [1,2]. For smaller sizes, deviations are experimentally observed suggesting description of the vibrational modes should rather be performed with an atomistic approach rather than with a “macroscopic” elastic body one. Using optical time-resolved spectroscopy, we show that this two approaches yield similar results down to the one nanometer scale, provided the environment of the nano-objects is properly taken into account. Acoustic vibration damping and its control will also be discussed, on the basis of time-resolved investigations of the acoustic vibration of single supported metal nano-objects.