Light-Absorption in Nano-Antennas—From Self-Heating to Reconfigurable Metasurfaces

In the last decade, optical nanoantennas have revolutionized light manipulation and control at the nanoscale. Light absorption was initially considered a purely detrimental process, reducing the efficiency of optoelectronic devices. Recently, however, it has attracted growing interest, enabling novel light-energy conversion pathways and offering intriguing opportunities for reconfigurable systems.<br/>In the first part of the talk, I will discuss self-induced optical heating effects in highly absorbing Silicon (Si) and Germanium (Ge) nanoresonators. In particular, I will show recent calculations demonstrating that, due to thermos-optical effects, self-heating can give rise to a complex, non-linear relationship between illumination intensity and temperature, even for moderate illumination intensities relevant for applications such as Raman scattering [1]. Subsequently, I will discuss how self-induced optical heating could be employed in optical devices and metasurfaces. In the second part of the talk, instead, I will discuss the opportunities of localized heating through metallic (plasmonic) nanoantennas. In particular, I will present our recent efforts in reducing the computational cost of photothermal energy dissipation in 3D arrays of nanoparticles and I will discuss the ensuing opportunities for material optimization.<br/>[1] Tsoulos, Tagliabue, Nanophotonics 9 (12), 3849-3861