MAGNOZZI M.

Silver is an extremely appealing metal for plasmonics due to its very low optical losses in the visible and near-ultraviolet range and its relatively low reactivity. Within the emerging field of thermoplasmonics, where light-metal interactions are exploited to generate heat on the nanometric scale, knowledge of temperature-dependent complex...

Silver represents, by and large, the best plasmonic metal available, due to its very low optical losses in a broad photon-energy range encompassing all the visible optical spectrum. Its performances are, more often than not, severely hampered by the presence of a few-nanometer thick surface-tarnish layer; thermal annealing under high-vacuum...

We report a real time, in-situ spectroscopic ellipsometry study of the temperature-induced solid-state dewetting of Au nanowires into nanoparticles. Very large spectral variations are observed at different temperatures. Analysis of the key features in the acquired spectra reveals two different regimes: up to 300 °C the variation in the optical...

Electromagnetically-heated metal nanoparticles can be exploited as efficient heat sources at the nanoscale. The assessment of their temperature is, however, often performed indirectly by modelling their temperature-dependent dielectric response. Direct measurements of the optical properties of metallic nanoparticles in equilibrium with a...

The performance of optical cavities in gravitational wave detectors (GWD) is negatively affected by the growth of ice layers when operating at cryo temperatures. Loss of performance begins when the ice overlayer is only a few-nm thick. Careful planning is then required to minimize, monitor and take into account the presence of ultrathin ice on...

Heterostacks composed of two-dimensional WS2 and graphene exhibit interesting opto-electronic properties, including ultrafast charge transfer and fast, efficient photodetection. The optical properties of WS2 are heavily influenced by the presence of graphene in the heterostack, yet, so far, their characterization in the whole visible range is...

We investigated the temperature-dependent optical response of ordered lattices of noninteracting gold-core/poly(N-isopropylacrylamide)-shell nanoparticles (NPs), a system with proven photothermal and sensing capabilities. For the first time on this system, we exploited in situ spectroscopic ellipsometry (SE) to determine the complex,...

We determine the optical properties of amorphous, mixed titania-tantala coatings as a function of the mixing ratio and thermal annealing. The Urbach energy is proposed as a good estimator of the quality of the coatings.

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...

We investigated the effects of ultrafast laser excitation of Au nanoparticles (NPs) having strong interparticle electromagnetic coupling by irradiating the NPs either at interband or plasmon-resonance wavelengths (13-100 J/m2 fluence regime). We observed that interband excitation is significantly more efficient than plasmonic excitation in...

Monolayer tungsten disulfide (WS2) has recently attracted a great deal of interest as a promising material for advanced electronic and optoelectronic devices such as photodetectors, modulators, and sensors. Since these devices can be integrated in a silicon (Si) chip via back-end-of-line (BEOL) processes, the stability of monolayer WS2 in BEOL...

Anti-reflective surfaces are of great interest for optical devices, sensing, photovoltaics, and photocatalysis. However, most of the anti-reflective surfaces lack in situ tunability of the extinction with respect to wavelength. This communication demonstrates a tunable anti-reflective surface based on colloidal particles comprising a metal core...

Excitons dominate the light absorption and re-emission spectra of monolayer transition-metal dichalcogenides (TMD). Microscopic investigations of the excitonic response in TMD almost invariably extract information from the radiative recombination step, which only constitutes one part of the picture. Here, by exploiting imaging spectroscopic...

The opto-electronic properties of semiconducting 2D materials can be flexibly manipulated by engineering the atomic-scale environment. This can be done by including 2D materials in tailored van der Waals (vdW) stacks, whose optical response is a function of the number and the type of adjacent 2D layers. This work reports a systematic...

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...