Litty, Irimpan; Nampoori, V P N; Radhakrishnan, P(Elsevier, 2008)
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Abstract:
In this Letter we present the spectral and nonlinear optical properties of ZnO–Ag nanocomposites prepared by colloidal chemical synthesis. Obvious enhancement of ultraviolet (UV) emission of the samples is observed and the strongest UV emission is over three times than that of pure ZnO. These nanocomposites show self-defocusing nonlinearity and good nonlinear absorption behaviour which increases with increasing Ag volume fraction. The observed nonlinear absorption is explained through two photon absorption followed by free carrier absorption. ZnO–Ag is a potential nanocomposite material for the UV light emission and for the development of nonlinear optical devices with a relatively small limiting threshold.
Senoy, Thomas; Sakthikumar, D; Yoshida, Yasuhiko; Anantharaman, M R(Springer, 2008)
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Abstract:
Sol–gel glasses with Fe3O4 nanoparticles having particle sizes laying in the range 10–20 nm were encapsulated
in the porous network of silica resulting in nanocomposites having both optical and magnetic
properties. Spectroscopic and photoluminescence studies indicated that Fe3O4 nanocrystals are embedded
in the silica matrix with no strong Si–O–Fe bonding. The composites exhibited a blue luminescence. The
optical absorption edge of the composites red shifted with increasing concentration of Fe3O4 in the silica
matrix. There is no obvious shift in the position of the luminescence peak with the concentration of Fe3O4
except that the intensity of the peak is decreased. The unique combinations of magnetic and optical
properties are appealing for magneto–optical applications.