Invited
Confinement of Light and GHz Sound in (Nano)Photonic Resonators

We describe plasmonic and semiconductor devices with nanometric dimensions where it is possible to confine photons (VIS-NIR) and acoustic phonons (GHz-THz frequencies) in a single resonant cavity.

Every physical property of a solid-state system that is determined by the position of the atoms is strongly affected by acoustic phonons. The control of the propagation of acoustic waves of GHz-THz frequencies is at the base of the phonon engineering, and thus of light-matter interactions. Advances in material science and fabrication techniques enabled the conception of devices with nanometric dimensions where it is possible to confine photons (VIS-NIR) and phonons (GHz-THz frequencies) in a single resonant cavity.

In this presentation I will describe the behavior of standard acoustic Fabry-Perot resonators based on semiconductor materials, and then present a plethora of devices able to control the interactions between light, sound and charge at the nanoscale. I will introduce some strategies to generate, manipulate and detect ultra-high frequency acoustic phonons using ultrafast lasers (pump-probe) and Brillouin scattering techniques. I will also introduce plasmonics into the field of nanophononics, and show how an array of metallic optical nanoantennas optimized to work at visible wavelengths can be tailored to generate and detect acoustic phonons.

The presented results open a new playground in the control of acoustic vibrations in solids, providing not only new tools to confine and control the dynamics of ultra-high frequency phonons but also a new platform to study topological effects, quantum phenomena and thermal transport properties.