Infrared nanosecond laser radiation in the creation of gold and copper nanoparticles

Metal nanoparticles inside glass present useful properties to photonic applications and have been object of several research works. In particular, laser beams have shown their potential in its creation and both ultraviolet beams with nanosecond pulses, and near-infrared beams with femtosecond pulses, have been used. In this paper, the authors add new possibilities by experimentally demonstrating that it is possible to achieve the same results by using near-infrared laser beams and nanosecond pulses. Copper and gold nanoparticles are created in silica-doped glass using nanosecond laser pulses in the near-infrared. Recorded absorption spectra of the glass samples before, and after laser irradiation and further annealing allowed measuring absorption peaks located at 537 nm for copper and 563 nm for gold, which are in accordance with the expected values. Based on Mie theory and using the full-width half maximum for those peaks, the average particle radii of the embedded nanoparticles was estimated to be about 7 nm for copper and 3 nm for gold nanoparticles, respectively.