Silicon metasurfaces with tunable electromagnetic resonances for nonlinear optical conversion

Dielectric metasurfaces sustain electromagnetic modes which can be exploited to enhance nonlinear frequency-conversion processes such as third-harmonic generation. In this work we employ electron-beam lithography to fabricate silicon metasurfaces supporting electromagnetic resonances with different quality factors (Q), ruled by the geometry. This allows to investigate the trade-off between resonant enhancement and matching the spectral bandwidth of the ultrafast excitation source. Both experiments and simulations indicate that higher values of Q do not a priori bring about a stronger third-harmonic generation, which correlates to the spectral overlap between the metasurface resonance and th…

Analisi di manufatti lignei provenienti dal Museo Diocesano di Palermo tramite Spettrometria di massa ToF-SIMS

Approccio multidisciplinare al resturo della statua di San Nicola di Mira: un caso studio

Surface and interface effects on the current-voltage characteristic curves of multiwall carbon nanotube-Si hybrid junctions selectively probed through exposure to HF vapors and ppm-NO2

The possibility to increase the efficiency of photovoltaic (PV) cells based on hybrid carbon nanotube (CNT)–Si heterojunctions is related to the ability to control the chemical properties of the CNT–Si interface and of the CNT bundle layer. In spite of the encouraging performances of PV cells based on multiwall (MW) CNT, so far few efforts have been made in the study of this device compared to single wall (SW) CNT–Si interfaces. Here, surface and interface effects on the current–voltage characteristic curves of MW CNT–Si hybrid junctions are investigated through exposure to HF vapors and to 10 ppm-NO2 and compared to the effects detected in SW CNT–Si junctions. Quite similar results in term…