Seminars Archive

Thermo-mechanics of a phononic crystal investigated by pump-probe optical techniques.

Abstract
The ultrafast thermal and mechanical dynamics of a two-dimensional lattice of metallic nanodisks has been studied by near-infrared pump-probe diffraction measurements over a temporal range spanning from 100 fs to several nanoseconds. It is shown how the impulsive heating of the nanodisks lunches a Surface Acoustic Wave (SAW) in the Si substrate and how the SAW frequency, in the GHz range, can be can be tailored changing the lattice periodicity. The evolution of the SAW is studied in details from its birth to its dissipation to the bulk. A possible application of the present experimental technique to the field of nanocalorimetry and thermal transport at the meso-scale is shown. (Rif. F. Parmigiani)