Formation and studies of highly nonlinear glass―copper nanocomposites

Reactive diffusion of hydrogen in copper-doped glasses has been analyzed, and the formation of copper nanoparticles via reduction of ionic copper has been numerically modelled. Simulated optical properties of glass―copper nanocomposites are compared with measured optical spectroscopy data,which demonstrated the resonance of optical absorption corresponding to surface plasmon resonance (SPR) in copper (-560 nm) nanoparticles. These samples were used in femtosecond self induced nonlinear transmission and pump-probe transmission measurements in the vicinity of the SPR. In pump-probe experiments bleaching of the samples due to the surface plasmon damping, as high as ΔT/T∼15% with 8.7 ps relaxation time, was observed. Transmission measurements showed reverse saturable absorption with a nonlinear absorption coefficient of 10 ―10 ―10 ―9 cm/W in copper-doped nanocomposite that corresponded to -30% light induced change in the absorption coefficient. The observed record picosecond SPR bleaching and reverse saturable absorption make glass-copper nanocomposites attractive for nonlinear optical applications.