Nonlinear optical properties and surface-plasmon enhanced optical limiting in Ag–Cu nanoclusters co-doped in SiO2 Sol-Gel films

• DOI: 10.1063/1.1804228
• Publication Date: 2004-11-22T23:06:20Z
• Authors: P. Prem Kiran; B. N. Shivakiran ...; D. Narayana Rao; Goutam De
• Keywords: Nanoclusters; Nanosecond; Picosecond

The nonlinear optical properties and the role of surface-plasmon resonance (SPR) on limiting (OL) Ag–Cu nanoclusters co-doped in SiO2 matrix prepared using sol-gel technique with a Cu∕Ag molar ratio 1, 2 3, respectively, are presented. studies were made second harmonic high-power nanosecond picosecond Nd:YAG lasers. These films show self-defocusing nonlinearity both pulses good absorption behavior pulse excitation. refractive index decreased decreasing particle size, whereas increased an increase Cu concentration. observed is explained by taking into account cumulative effect intraband interband mechanisms. excitation near SPR resulted enhanced OL increasing No such concentration dependence when Ag, however, threshold reduced approximately 10–17 times. Excitation at wavelengths far below Ag has not shown any behavior. major contribution toward to be from possible energy transfer within higher unoccupied states Ag. Although scattering intensities, its found much less than that assisted transfer.