Observation of surface plasmon resonance of silver particles and enhanced third-order optical nonlinearities in AgCl doped Bi_2O_3-B_2O_3-SiO_2 ternary glasses

摘要

Bi_2O_3-B_2O_3-SiO_2 ternary glasses embedded with Ag nanoparticles were prepared by introducing AgCl into the bismuthate glasses using conventional melt quenching method and characterized by several experimental techniques. Scanning electron microscopic studies indicated the formation of Ag contained nanoclusters which crack and become regular with increase of AgCl content in these composites. Optical absorption spectra of the nanocomposites showed the presence of absorption band of surface plasmon resonance (SPR) due to Ag nanoparticles at ~600 nm. Z-scan measurement with femtosecond laser was used to investigate third-order optical nonlinearities of the nanocomposites. The results show that the nonlinear refraction γ was dramatically increased up to 30 times by the appearance of Ag nanoparticles when excited within its SPR region, while nonlinear absorption due to two-photon absorption exhibited opposite tendency or even saturated behavior. The calculation of figure of merit suggests that the Ag particle embedded Bi_2O_3-B_2O_3-SiO_2 glass composites are promising candidates for optoelectronic devices.