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The properties of graphene oxide foils were modified by excimer laser irradiation at different fluences and times. The irradiations were performed in air and in vacuum using a pulsed UV laser operating at 248-nm wavelength and 23-ns pulse duration. Measurements of ablation yield, microscope surface morphology and Raman spectroscopy were performed. The residual surface shows a significant oxygen reduction due to the removing of functional oxygen groups, a thickness reduction due to the removal of graphene layers depending on the used laser shots and a presence of defects in the graphene sheets as evident by the Raman spectroscopy investigation.

Spherical gold nanoparticles (NPs), 10 nm in diameter, have been dispersed in a type of polydimethylsiloxane, whose polymerisation requires accurate temperature control. At the temperature of 100°C, the polymerisation of the polydimethylsiloxane matrix is completed in 15 min, whereas at room temperature (∼20°C), it takes about 24–48 h. Gold NPs were incorporated into polydimethylsiloxane after which the resulting nanocomposites were placed in an oven preheated to 100°C for different curing times. Both porous and bulk nanocomposites were obtained using a bottom-up approach. Polydimethylsiloxane (PDMS) nanocomposites with the weight-percentage concentration of 0.2% of Au NPs were cured for 15, 30 and 45 min. Different curing times have affected the Au-NP properties. The network of porous PDMS nanocomposite promotes a uniform anchoring of the gold NPs. The porous PDMS nanocomposite samples, prepared using the sugar-template method, have been compared with the bulk counterpart to obtain a full characterisation of the material. The dependence of the morphological and electrical properties of gold NPs on their size has been studied by atomic-force microscopy and two-point-probe electrical-conductivity measurement. The optical performance of the bulk PDMS nanocomposites has been analysed by ultraviolet–visible (UV–vis) spectroscopy in the transmission mode. An enhancement of the absorption was observed after the increase of both the nanocomposite-curing time and the percentage of the Au NPs used as fillers. The fabricated nanocomposite can be used to manufacture optical-sensing devices, switches in optoelectronics and optical waveguides.

Proton acceleration can be induced by non-equilibrium plasma developed by high-intensity laser pulses, at 1016 W/cm2, irradiating different types of thin polyethylene targets. The process of proton acceleration and directive yield emission was investigated, optimizing the laser parameters, the irradiation conditions, and the target properties. The use of 600 J pulse energy, a laser focalization inducing self-focusing effects and advanced targets with embedded nanoparticles and optimal thicknesses, has permitted to accelerate forward protons up to the energies of about 6 MeV and amount of the order of 1015 H+/pulse. High proton energy is obtained using thin foils enriched with gold nanoparticles, whereas high proton yield is obtained using targets with a thickness of about 10 μm. The plasma diagnostics using SiC semiconductor detectors in time-of-flight configuration was fundamental to monitor the optimal conditions to improve the plasma processes concerning the ion acceleration and the X-ray and relativistic electron emission.

We report on a very compact desk-top transmission extreme ultraviolet (EUV) microscope based on a laser-plasma source with a double stream gas-puff target, capable of acquiring magnified images of objects with a spatial (half-pitch) resolution of sub-50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi-monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy.

Measurements of ion acceleration in polymethylmethacrylate foils covered by a thin copper film irradiated by fs laser in target normal sheath acceleration regime are presented. The ion acceleration depends on the laser parameters, such as the pulse energy; depends on the irradiation conditions, such as the focal point position of the laser with respect to the target surface; and depends on the target properties, such as the metallic film thickness. The proton acceleration increases in the presence of the metallic film enhancing the plasma electron density, reaching about 1.6 MeV energy for a focal position on the target surface. The plasma diagnostics uses SiC detectors, absorber foils, Faraday cups, and gafchromic films. Employing p-polarized laser light and a suitable oblique incidence, it is possible to increase the proton acceleration up to about 2.0 MeV thanks to the effects of laser absorption resonance due to plasma waves excitation.