Nonlinear optical properties and surface-plasmon enhanced optical limiting in Ag-Cu nanoclusters co-doped in SiO{sub 2} Sol-Gel films

Journal Article · Wed Dec 01 00:00:00 EST 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1804228· OSTI ID:20658111

Kiran, P Prem; Shivakiran Bhaktha, B N; Rao, D Narayana; De, Goutam ^[1]

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1. School of Physics, University of Hyderabad, Hyderabad - 500 046 (India)

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

• OSTI ID: 20658111
• Journal Information: Journal of Applied Physics, Vol. 96, Issue 11; Other Information: DOI: 10.1063/1.1804228; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
COMPOSITE MATERIALS
COPPER
DOPED MATERIALS
ENERGY TRANSFER
NANOSTRUCTURES
NEODYMIUM LASERS
NONLINEAR OPTICS
PARTICLE SIZE
PLASMONS
PULSES
REFRACTIVE INDEX
RESONANCE
RESONANCE PARTICLES
SCATTERING
SILICON OXIDES
SILVER
SOL-GEL PROCESS
WAVELENGTHS