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扫描电镜加工铌酸锂晶体电畴反转光栅的研究 总被引:3,自引:0,他引:3
本文简单介绍了非线性晶体相位匹配和铌酸锂光波导准相位匹配倍频原理,开展了扫描电子显微镜电子束辐照反转极化实验,分析了实验结果,摸索出合适的工艺条件,证明利用扫描电镜可以加工出满足准相位匹配条件的电畴反转我栅。 相似文献
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采用汽相输运平衡技术制备出了高质量近化学计量比掺镁铌酸锂晶体 ,系统研究了晶体中的 [Li]/ [Nb]比含量对其畴极化电场的影响 .实验结果表明 :随着晶体中 [Li]/ [Nb]比的提高 ,畴极化反转电场呈明显下降趋势 ,使用近化学计量比掺镁铌酸锂晶体 ,我们在 3.5± 0 .1kV/mm大小的外加极化电场条件下 ,成功地实现了 1.0mm厚度的周期极化畴反转 .我们用铌酸锂晶体的缺陷模型对实验结果给出了合理的解释 . 相似文献
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铌酸锂晶体电子结构和光学性质计算 总被引:1,自引:1,他引:1
使用基于从头计算平面波赝势法的CASTEP量化软件计算了铌酸锂(LiNbO3)晶体的电子能带结构和线性光学系数,采用耦合微扰方法(CPHF)计算了铌酸锂晶体的非线性光学系数.折射率和倍频系数的计算结果与实验结果基本符合,计算表明铌酸锂晶体中Nb原子的4d轨道电子态和O原子的2p轨道电子态发生了明显杂化.通过分析铌酸锂晶体的价带顶和导带底电子态密度的组成特点可知这些轨道电子态的杂化是其非线性光学效应的主要来源,同时计算还表明铌酸锂晶体中Li-O键具有明显的共价键性. 相似文献
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测量了一批不同组分的铌酸钾锂晶体Raman光谱,发现晶体中位于C格位的Li离子浓度对晶体Raman光谱产生了强烈的影响:低Li含量晶体中[NbO6]^7-八面体所对应的3个Raman特征光谱线没有发生峰分裂,在100~400cm^-1范围出现的小峰与C格位Li离子浓度相关;当晶体中Li离子浓度增加时,与v5所对应的Raman峰在散射几何为X(ZY)Z对应的光谱中加宽.v2振动模式在两种散射几何中均出现分裂峰,并在100~400cm^-1范围出现小峰数量增多;当Li离子浓度接近晶体化学组分时,微扰进一步加强,v5所对应峰分裂成3个峰,v1和v2振动模式发生部分分裂,在100~400cm^-1范围小峰更为突出. 相似文献
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铁电晶体铌酸钾锂的拉曼和FT—IR光谱 总被引:2,自引:0,他引:2
用提拉法生长了完整透明的铁电铌酸钾锂晶体 .利用X 射线荧光光谱法测量分析了晶体的组成 .采用X 射线测量了晶体的结构 .用结构完整、组分均匀 ,尺寸为 6× 6× 7(a×b×c)mm3 的晶体样品 ,测量了晶体的拉曼光谱和红外折射光谱 .与其它钨青铜类晶体的晶格振动光谱进行比较 ,铌酸钾锂晶体中对称弯曲振动模式v5在拉曼光谱中分裂为 3个拉曼峰 ,反对称伸缩振动模式v3 和反对称弯曲振动模式v4在红外反射光谱中所对应的峰被加宽 ,v4被轻微分裂 .这表明晶体中这位于C格位的Li离子对晶体中铌氧八面体的拉曼光谱和红外反射光谱有较大的影响 相似文献
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Reversible resistance change at room temperature by polarisation switching is reported in ferroelectric single crystals. Resistance switching up to six orders of magnitude in Mg-doped LiNbO/sub 3/ was found. The resistance change is caused by the polarisation switching and increases with Mg concentration. Based on these results, continuous switching properties and memory behaviours were demonstrated. 相似文献
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Courjal N. Porte H. Hauden J. Mollier P. Grossard N. 《Lightwave Technology, Journal of》2004,22(5):1338-1343
Domain inversion under coplanar waveguide electrodes is proposed to improve the frequency-chirping behavior of Z-cut LiNbO/sub 3/ Mach-Zehnder modulators. This is achieved by introducing a phase reversal electrode section in tandem with inverted ferroelectric domains. The method opens the way to broad-band single-drive modulators with predetermined chirp parameter. The experimental results obtained at 10 Gb/s confirm the possibility of lowering the chirp parameter of a Z-cut modulator, while keeping a halfwave voltage lower than 5 V. 相似文献
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A new technique for fabricating domain inversion regions in -c face LiNbO/sub 3/ by thermal oxidation of Ti is reported. This technique can minimise refractive index changes in such regions, thus it is suitable for quasiphase-matching (QPM) second harmonic generation (SHG). A prototype QPM waveguide SHG device is also demonstrated.<> 相似文献
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Ferroelectric Pt/PZT/Pt capacitors with different PZT orientations are characterized before and after electrical fatigue. (111)c-oriented, tetragonal PZT is characterized by abrupt 180° switching and very high-quality hysteresis loops but is very prone to electrical fatigue, while the 90° switching which is dominant in unsaturated and/or unpoled (100)c PZT films results in slanted loops with low polarization but high endurance. 相似文献
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E. A. Vilkov 《Journal of Communications Technology and Electronics》2008,53(4):443-452
A tetragonal ferroelectric in the presence of a moving superlattice of 180-degree domain walls is considered. The spectral properties of shear waves in such a material are analyzed in the quasi-static approximation. The spectrum of elastic shear waves is represented as alternating allowed and forbidden bands. It is demonstrated that, owing to the motion of domain walls, the degeneration of the roots of the dispersion equation is eliminated. This effect is manifested in both the spectral structure and the amplitude and phase characteristics of eigenwaves in the periodic structure under study. The ferroelectric’s acoustic nonreciprocity induced by the motion of domain walls is predicted. 相似文献
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The characteristics of the ferroelectxic domain inversion structures fabricated by applying voltage at room temperatture in Z-cut congruent LiNbO3 and stoichiometric LiNbO3 crystals were examined. The voltage required for domain reversal in congrueat crystals is about 2.8 times larger than the voltage for stoichiometric crystals. The periodicity of the sstoichiometric crystals are more uniforn than that of the congruent crystals. 相似文献
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对铈铁掺杂铌酸锂(Ce:Fe:LiNbO3)晶体进行氧化、还原处理。通过红外光谱、紫外可见吸收光谱测试了晶体样品的组成和缺陷结构。采用透射光斑畸变法测试了晶体样品的抗光损伤能力,结果表明:生长态晶体比还原态晶体的抗光致散射能力基本上高一个数量级,氧化态的晶体要比还原态的晶体高两个数量级。采用二波耦合实验测试了晶体样品的光折变性能,结果表明:从氧化到生长再到还原态,衍射效率逐渐降低,响应时间缩短,光折变灵敏度增加,动态范围逐渐降低。 相似文献