Investigation of optical properties of hydrogenated targets for proton acceleration by plasma-laser

Proton acceleration by laser-generated plasmas in TNSA conditions are becoming of peculiar interest for ion beam applications in Bio-Medicine. Different techniques of thin film deposition, such as ion sputtering, pulsed laser deposition, spin coating and powder sintering 130 have been employed to prepare hydrogenated targets containing nanostructures to be irradiated in TNSA conditions. At Messina University and at PALS laboratory in Prague nanosecond and sub-nanosecond laser pulses at intensities between 1010 W/cm2 and 1016 W/cm2 have been employed to drive ions and protons acceleration. Measurements demonstrated that the maximum kinetic energy conferred to protons is 1 keV and 5 MeV in the two cases, respectively. In order to understand the amount of light energy released to a solid target during lasermatter interaction become crucial to investigate on the laser reflectivity and on the absorption coefficient of the irradiated samples. In this work investigations of the optical properties of the thin films laser irradiated at Messina and Prague are presented and discussed.