Thèses

Lundi 26 Février 2018 à 10h30.

Optics and acoustics with a single nano-object: environment effects

''In this thesis, the properties of a single metal nanoparticle have been tuned by altering its environment and its morphology. Specifically, in the first part of this work, the surface plasmon resonance of individual gold nanobipyramids has been experimentally studied under a pressure-adjustable surrounding, and its evolution physically interpreted through theoretical modeling. In order to access to the optical response under high-pressure at single-particle level, a challenging combination of a spatial modulation spectroscopy (SMS) microscope with a diamond anvil cell has been achieved. In the second part of the thesis, the acoustic vibrations of individual gold nanodisks on sapphire substrate have been experimentally characterized by combining the SMS microscope with an ultrafast pump&probe setup. The dependence of their damping on the disk morphology has enlightened the presence of quality-factor enhancements. Numerical modeling has provided a physical insight for the observed phenomena, showing that mode hybridizations occur at specific aspect ratios, reducing the acoustic energy loss through the nano-object/environment interface.''