Study On Second-order Nonlinear Optical Properties In Transparent Glass-ceramic

With the coming of information times, second-order nonlinear optical materials will have wide applications in the fields of optical information processing, optical sensing, and telecommunications. Among these materials, glass-ceramics are one of the most promising materials because of their wide-range transparency, high damage threshold, chemical stability , thermal stability , fast photo response and large second-order nonlinear optical coefficient.In this thesis, the melt-quenching method was employed to fabricate 16Li₂O-2Nb₂O₅-80B₂O₃-2TiO₂ , 62TeO₂-8BaO-8TiO₂-22Li₂O and x₁TiO₂-X₂BaO-X₃B₂O₃ (x₁=2, 4, 8, 12, 16; x₂: x₃=8: 9) as-quenched glasses. Differential thermal analyses were made to select appropriate heat treatments to crystallize the samples. Maker fringe technique was introduced to investigate the second-harmonic generation of the crystallizing glasses heat treated in different conditions.In 16Li₂O-2Nb₂O₅-80B₂O₃-2TiO₂ glass system , the as-quenched glasses were heat treated at 530℃for 1h,3h,5h,after heat treatment the transmission droped obviously, the X-ray diffraction result showed that the transparent crystallizing glasses containing LiNbO₃ crystal were acquired. The outcome of the Maker fringe test demonstrated that the crystallizing glass possess evident second-harmonic generation effect that originated from the LiNbO₃ crystal.In 62TeO₂-8BaO-8TiO₂-22Li₂O glass system, the as-quenched glasses were heat treated in different temperature and period. After heat treated, the crystallized glasses were test by the X-ray diffraction, and the result showed that only Li₂TeO₃ crystal was found ,and the spontaneous preferred orientation occurred in the glass. Maker fringe test showed that the crystallized glass possessed evident second-harmonic generation effect that originated from the Li₂TeO₃ crystal.In x₁TiO₂-x₂BaO-x₃B₂O₃ glass system , the x₁=2,4,8,12 and 16 glasses were heat treated in different temperature and period respectively , the result showed that the glasses with x₁=4,8 and 12 crystallized at a comparative low temperature 620℃, while the compositions with x₁=2 and 16 need higher temperature and longer period to crystallize. The X-ray diffraction result showed theβ-BaB₂O₄ and BaTi(BO₃)₂ crystals were acquired together in most of the samples. The SEM images of the x₁=4 samples showed the crystals regularly distributed on the two surface of the glasses, the average size of the crystals increased while the heat treatment period prolonged, the thickness of the crystallized layer was approximate 25μm in the x₁=4 crystallized sample heat treated at 620℃for 8h ,and the average size of the crystals was 1μm,themaximum value of theχ⁽²⁾ =15Pm/V.