Metallic nanoparticles in thin foils for laser ion acceleration

Abstract

Metallic nanoparticles have been obtained by 10$¹⁰$ W/cm$²$ Nd:YAg laser ablation in liquid at different irradiation conditions. The nanoparticles were based on Au, Ag, Ti and Cu with means size ranging between 10 nm and 100 nm at different concentrations. Nanoparticles were analyzed with optical absorption spectroscopy in the wavelength range 300-1000 nm. The resulting solutions have been deposited or embedded on different thin polymeric substrates (mylar, nuclepore, polyethylene). The laser irradiation of the prepared thin targets produces a backward plasma emission characterized by ion acceleration. Plasma was monitored in vacuum through ion collectors employed in time of flight configuration. The measurements reveal a significant ion acceleration enhancement of proton and carbon ions in the case of metal nanoparticles with respect to the case without, due to the increment of the laser energy deposition in the prepared targets for Surface Plasmon Resonant (SPR) absorption effect.