Photonic quantum technologies are a promising platform for a large variety of applications ranging

from secure long-distance communications to the simulation of complex phenomena. Among the material

platforms under study, semiconductors offer a wide range of functionalities opening several opportunities for

the development of integrated quantum photonic circuits. AlGaAs is particularly attractive to monolithically

integrate active and passive components since it combines high second order nonlinearity, electro-optic effect

and direct bandgap. In this talk, I will present the work of our team on the generation of quantum states of

light in the telecom range with nonlinear AlGaAs chips working at room temperature.

Memristive devices are an emerging new type of devices operating at the scale of a few or even single atoms. They largely exploited for emulating the electrical function of synapses and are thus currently investigated for performing in-memory and neuromorphic computing. In this contribution, we report the observation of a novel feature in these devices. We show that memristors can also emit photons during their activity. We identified three mechanisms producing photons with vastly different properties. The crossover between emission regimes depends on the history of the memristor and its operating conductance. Our results suggests that this new generation of memristor pave the way for multidimensional neural networks using both electrons and photons as information carrier.

Femtosecond pump and probe optical spectroscopy has been employed for investigating ultrafast cooling of metal and carbon nano-objects, leading to quantitative determination of the physical parameters ruling thermal exchanges, such as thermal boundary resistance and thermal conductivity. Experimental and theoretical investigations on plasmonic nanoparticles and carbon nanotubes will be reviewed, as well as their applications to photoacoustics.

Silicon nanowires (Si NWs) represent one of the most promising platforms to be integrated into modern nanodevices. The fabrication of a dense array of vertically aligned ultrathin Si NWs using a low-cost, maskless approach and compatible with Si technology will be here demonstrated. Si NWs with efficient light emission at room temperature (RT) represent a great advance industry, paving the way for a wide range of unexpected photonic applications. In this work I will show the realization of a new hybrid material based on the luminescence of Si NWs and two different dyes for light-harvesting antennas applications, without any surface functionalization and with energy transfer efficiencies higher than 90%. The luminescence of Si NWs has also been used for sensing applications by the realization of highly sensitive sensors for the detecting of low concentrations of toxic gases. These sensors allow the detection of toxic gases below the threshold limits for human health, through both optical and electrical transduction. The achievement of light emission from silicon-based materials represents a revolution in the industrial field, as it paves the way for new Si applications.

In this work, we present the first experimental results on a Schottky photodetector based on Silicon Carbide (SiC) and Graphene (Gr) designed to operate in the visible spectral range. While SiC has been extensively investigated for various applications in the ultraviolet domain, there are only a few works in the visible range, where SiC exhibits negligible optical absorption. To overcome such intrinsic limit of SiC, we exploit the properties of a single layer of Gr to enhance, significantly, the photodetection performance of the device operating, in our experiments, at the wavelength of λ=633 nm. From the current-voltage (I-V) characteristics, a series resistance of 3.7 kΩ, an ideality factor of 8.4, and the zero-bias Schottky barrier height of 0.755 eV have been calculated. Finally, the internal responsivity, as function of the reverse bias applied to the device, has been measured demonstrating a maximum value exceeding 1 mA/W at -5V.

You Two-dimensional nanomaterials, such as MoS2 nanosheets, have been attracting increasing

attention in cancer diagnosis and treatment, thanks to their peculiar physical and chemical properties.

Although the mechanisms which regulate the interaction between these nanomaterials and cells are not yet

completely understood, many studies have proved their efficient use in the photothermal treatment of cancer,

and the response to MoS2 nanosheets at the single-cell level is less investigated. Clearly, this information can

help in shedding light on the subtle cellular mechanisms ruling the interaction of this 2D material with cells

and, eventually, to its cytotoxicity. Here, as a first presented biomedical application of nanomaterials, we use

confocal micro-Raman spectroscopy to reconstruct the thermal map of single human cancer cells targeted

with MoS2 under continuous laser irradiation. The experiment is performed by analyzing the water O-H

stretching band around 3,400 cm−1 whose tetrahedral structure is sensitive to the molecular environment and

temperature. Compared to fluorescence-based approaches, this Raman-based strategy for temperature

measurement does not suffer fluorophore instability, which can be significant under continuous laser

irradiation. As a second biomedical application, we focus on preliminary obtained by the fabrication and use

of magnetic nanomaterials in Magnetic Resonance Imaging, tested on 3D-printed phantoms.