Lithium niobate bulk crystallization promoted by CO_2 laser radiation

摘要

The crystallization induced by laser radiation is a very promising technique to promote glass/ceramic transformation, being already used to produce crystalline patterns on glass surfaces. In this work, a SiO_2-Li_2O-Nb_2O_5 glass, prepared by the sol-gel route, was submitted to CO_2 laser radiation and conventional heat-treatments in order to induce the LiNbO_3 crystallization. The structure and morphology of the samples prepared by both routes was analyzed as a function of exposure time, radiation power and heat-treatment temperatures by XRD, Raman spectroscopy and SEM. The results reveal a correlation between the crystallization degree of LiNbO_3 particles and glass matrix with the heat treatment type and experimental parameters. An heat-treatment at 650 ℃/4 h was necessary to induce crystallization in heat treatments samples while 4 W/500 s was enough for laser radiation ones, corresponding a reduction time processing of ～14 000 s.