DELLA VALLE G.

Bidirectional nanoantennas are of key relevance for advanced functionalities to be implemented at the nanoscale and, in particular, for color routing in an ultracompact flat-optics configuration. Here we demonstrate a novel approach avoiding complex collective geometries and/or restrictive morphological parameters based on cross-polarized...

Hybrid plasmonic-semiconductor assemblies are receiving considerable attention due to the possibility to achieve hot-carrier-based photodetection. In this context, 2D transition metal dichalcogenides (TMDs) coupled to metal nanostructures are very promising. However, the plasmon-to-TMD carrier injection process is extremely challenging to...

The femtosecond evolution of the electronic temperature of laser-excited gold nanoparticles is measured, by means of ultrafast time-resolved photoemission spectroscopy induced by extreme-ultraviolet radiation pulses. The temperature of the electron gas is deduced by recording and fitting high-resolution photoemission spectra around the Fermi...

The excitation of plasmonic nanoparticles by ultrashort laser pulses sets in motion a complex ultrafast relaxation process involving the gradual re-equilibration of the system's electron gas, lattice, and environment. One of the major hurdles in studying these processes is the lack of direct measurements of the dynamic temperature evolution of...

The study of nonthermal electrons, generated upon photoexcitation of plasmonic nanostructures, plays a key role in a variety of contexts, from photocatalysis and energy conversion to photodetection and nonlinear optics. Their ultrafast relaxation and subsequent release of energy to a low energy distribution of thermalized hot electrons has been...

Flat optics nanoarrays based on few-layer MoS2 are homogeneously fabricated over large-area (cm2) transparent templates, demonstrating effective tailoring of the photon absorption in two-dimensional (2D) transition-metal dichalcogenide (TMD) layers. The subwavelength subtractive re-shaping of the few-layer MoS2 film into a one-dimensional (1D)...

A cost effective method to tailor the optical response of large-area nanosheets of 2D materials is described. A reduced effective metalayer model is introduced to capture the key-role of the out-of-plane component of the dielectric tensor. Such a model indicates that the optical extinction of 2D materials can be strongly altered by controlling...