Influence of the Devitrification Mechanism on Second Harmonic Generation Efficiency and Transparency in Ba2NaNb5O15 Nanostructures

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• 作者：Esther Fanelli ; Claudio Giannetti ; Antonio Aronne ; Stefania Pagliara ; Serena Esposito ; Gabriele Ferrini
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：December 27, 2012
• 年：2012
• 卷：116
• 期：51
• 页码：26874-26880
• 全文大小：396K
• 年卷期：v.116,no.51(December 27, 2012)
• ISSN：1932-7455

文摘

The crystallization behavior of two new stable glasses belonging to the BaO鈥揔₂O鈥揘a₂O鈥揘b₂O₅鈥揝iO₂ system, synthesized by the melt-quenching technique, was studied with the aim to obtain nanostructured glasses based on tungsten鈥揵ronze phases. Nanostructured samples with valuable second harmonic generation (SHG) activity were obtained starting from 8BaO路15Na₂O路27Nb₂O₅路50SiO₂ glass after suitable heat treatments performed in the glass transition range, by means of the bulk nucleation mechanism. The influence of the devitrification mechanism on the SHG efficiency was clarified with particular reference to the effect of structural modifications on the transparency of the nanostructured glasses. These samples are formed by Ba₂NaNb₅O₁₅ nanocrystals (about 15 nm in size) randomly dispersed in a phase-separated amorphous matrix. Their SHG efficiency is partially impaired by the Rayleigh scattering originated by the nanocrystals. These nanostructured glasses can be useful when the generation efficiency is not an issue, as in the diagnostics for ultrafast lasers, due to the independence of the second harmonic generation from the polarization state of the laser light and no need for preferential material orientation.