Sr0.61Ba0.39Nb2O6薄膜的电光特性

用激光脉冲沉积(PLD)法在MgO(001)衬底上成功地生长、制备出了外延Sr_0.61Ba_0.39Nb₂O₆(SBN61)电光薄膜;通过SBN61电光薄膜椭偏光谱测量的分析研究,得到了SBN61电光薄膜的光学常数;通过电致双折射方法对生长在(001)MgO衬底上的SBN61薄膜的电光性能进行了测量研究,发现SBN61电光薄膜电致双折射的变化Δn与所加电场E成平方关系,其二次电光系数R=0.21×10^-16(m/V)²。     

薄膜光学 光学薄膜参数测试

O484．5 2005032081 铁电SBN薄膜电光系数的测量及其在波导中的应用= Measurement of electrooptic coefficients in SBN60 thin films and their applications in Mach-Zehnder type waveguide modulators[刊,中]／沈智如(浙江大学现代光学 仪器国家重点实验室．浙江,杭州(310027)),叶辉…∥光 学学报．-2005,25(1)．-121-125 利用溶胶-凝胶法在MgO(001)衬底上获得c轴择优 取向的铁电铌酸锶钡(SBN)薄膜,主要介绍MgO(001)衬     

采用接触式极化法研制有机聚合物电光光波导调制器

结合器件的整体结构考虑，对接触式极化方法和工艺进行了研究，基于接触式极化法，设计并制作了聚合物电光光波导相位和偏振调制器。通过测量器件的偏振调制特性，在1550nm光波波长下，获得了最大电光系数为llpm／V，电光相位调制器的半波电压为45V。     

基于嵌入填充层的薄膜铌酸锂-氮化硅电光调制器

提出一种异质集成型薄膜铌酸锂电光调制器,由底部氮化硅波导、中间BCB黏合层、顶部铌酸锂薄膜构成调制区波导结构,调制电极位于铌酸锂薄膜的上部且二者之间填充了低折射率的SiO₂,以利于实现折射率匹配并降低光损耗、微波损耗。进一步利用马赫-曾德尔干涉仪结构,设计了相应的电光调制器,并提出一种倒台阶型薄膜结构,该结构可实现输入、输出波导与调制区波导的高效耦合。对该电光调制器进行行波高速匹配设计,所得器件的半波电压长度积为1.77 V·cm,3 dB调制带宽为140 GHz,且调制区长度仅为5 mm。所提器件结构有望在大带宽薄膜铌酸锂电光调制器设计中发挥优势,助力薄膜铌酸锂光子集成器件的快速发展。     

基于电光聚合物的表面等离激元调制器

基于电光聚合物,提出了一种结构简单,尺寸小,效率高的表面等离激元(SPP)调制器.该调制器采用M-Z干涉仪结构的金属波导,金属周围是均匀极化后的电光聚合物,通过在金属波导两臂间加电压对聚合物折射率进行调制,折射率调制再通过M-Z干涉仪结构转化为对金属波导中SPP强度的调制. 通过求解金属波导附近的电场分布,并结合SPP场分布的特点,在理论上说明了这种结构可以通过外加电压有效地调制金属波导输出端SPP的强度,调制所需的半波电压约为2.8V. 关键词： 表面等离激元 电光调制 电光聚合物     

铁电钾钠铌酸锶钡薄膜电光性能的研究

采用溶胶-凝胶法在氧化镁单晶衬底上制备了符合化学计量比的完全填充型铁电钾钠铌酸锶钡(KNSBN)薄膜，通过X射线衍射，摇摆曲线，X射线Φ扫描，扫描电子显微镜等方法研究了薄膜的微结构，采用Adachi法研究了薄膜的电光特性. 实验发现，KNSBN薄膜在氧化镁(001)单晶衬底上沿c轴外延生长，K⁺，Na⁺的引入有效地提高了薄膜的横向电光系数r₅₁. 成分为K_0.2Na_0.2Sr_0.24Ba_0.56Nb₂O₆, K_0.2Na_0.2Sr_0.6Ba_0.2Nb₂O₆, K_0.2Na_0.2Sr_0.72Ba_0.08Nb₂O₆的三种KNSBN薄膜的r₅₁值分别为108.52pm/V, 119.98pm/V, 126.96pm/V，r₅₁的数值随Sr²⁺含量增加而增大. 关键词： 横向电光系数 钾钠铌酸锶钡 外延生长     

以MgO为缓冲层的硅基铌酸锶钡薄膜取向特性与其波导结构的设计研究

采用溶胶－凝胶法在Si(100)基片上制备出择优取向的MgO薄膜,随后在其上生长出具有择优取向的铌酸锶钡铁电薄膜.实验发现,MgO缓冲层的应用可以大大提高SBN薄膜的择优取向性能.同时,用五层对称理想波导耦合模理论,以SBN为波导层,分析了波导损耗与厚度的关系. 通过对计算出的理想结果与实际相结合,以及对SBN在生长过程工艺与损耗关系的研究,制备出高质量、低损耗的SBN薄膜,为其在电光波导调制器等微系统中的应用打下良好的基础.     

光纤马赫-曾德尔干涉法测量极化聚合物的电光系数

报道了用光纤马赫曾德尔干涉法测量极化聚合物电光系数的方法和原理。该方法不仅可以测量聚合物薄膜的电光系数而且可以测量聚合物波导的电光系数,并且该方法可以同时测量聚合物的电光系数张量元r13和r33。该方法最突出的优点是不必在聚合物薄膜的表面制备第二个电极,因此尤其适合于在电光聚合物试制阶段测试聚合物的电光系数。干涉仪的输出被反馈到参考臂中控制相位偏置点的压电陶瓷,从而实现对干涉仪相位偏置点的闭环控制,因此降低了对环境稳定性的要求并且提高了测量精度。实际测试了极化聚合物薄膜PMMA-DR1的电光系数张量,其测量值r13=8.3 pm/V,r33=25.7 pm/V。     

弛豫铁电单晶0.93Pb(Zn1/3Nb2/3)O3-0.07PbTiO3的电光性能研究

以波长为632.8 nm的He-Ne激光作为光源,研究了三方相弛豫铁电单晶0.93Pb(Zn1/3Nb2/3)O3-0.07PbTiO3在室温下的折射率和线性电光性质.通过测量晶体的布儒斯特角,确定了单晶的两个主轴折射率:no=2.466,ne=2.488.利用改进的马赫-泽德尔干涉法测量了单晶的线性电光系数:r33=71 pm/V,r13=4 pm/V.计算得到有效电光系数rc=67 pm/V及半波电压Vπ=610 V.单晶优异的电光性能使其在激光调制与偏转领域有着巨大的应用潜力.     

M-Z型极化DANS聚合物电光波导强度调制器研究

研究了Mach-Zehnder型极化聚合物电光波导强度调制器的制备工艺.器件采用DANS (4-dimethylamino-4′nitro-stlibene)聚合物为电光波导材料，由电光波导层、上下介质缓冲层、上下金属电极层构成五层波导结构.对五层光波导各层之间的光学、化学以及微加工工艺的相互兼容性进行了深入研究.采用紫外光漂白方法制备出侧壁光滑的条波导，采用钨丝电晕极化方法对DANS聚合物波导进行有效极化，使其具有电光特性.通过优化器件制备工艺，研制出工作波长为1300 nm的M-Z型电光波导强度调制器原型器件.实验测得器件半波电压约为10 V，调制带宽约为1 GHz.     

Electro-optic properties of epitaxial Sr<Subscript>0.6</Subscript>Ba<Subscript>0.4</Subscript>Nb<Subscript>2</Subscript>O<Subscript>6</Subscript> films grown on MgO substrates using Li<Subscript>x</Subscript>Ni<Subscript>2-x</Subscript>O buffer layer

Textured Li_xNi_2-xO (LNO) thin films have been fabricated on (001)MgO substrates by pulsed laser deposition technique. The as-deposited LNO films shows a conductivity of 2.5×10^-3 Ω m and possess a transmittance of about 35% in the visible region. Subsequent deposition of Sr_0.6Ba_0.4Nb₂O₆ (SBN60) thin film on these LNO-coated MgO substrates resulted in a textured SBN layer with a 〈001〉 orientation perpendicular to the substrate plane. Phi scans on the (221) plane of the SBN layer indicated that the films have two in-plane orientations with respect to the substrate. The SBN unit cells were rotated in the plane of the film by ± 8.2° as well as ± 45° with respect to the LNO/MgO substrate. Besides the highly (00l)-orientation, the SBN films also exhibited a dense microstructure as shown by scanning electron microscopy. The electro-optic coefficient (r₃₃) of the SBN film was measured to be 186 pm/V. On the basis of our results, we have demonstrated that the LNO film can be used as a buffer layer as well as a transparent bottom electrode for waveguide applications. The SBN/LNO heterostructure is also a suitable candidate for integrated electro-optics devices. PACS  42.79.Gn; 42.82.Et; 78.20.Ci     

铌酸锶钡薄膜的微结构与电光性能的研究

本文叙述了使用溶胶凝胶法在MgO(0 0 1)的衬底上制备铌酸锶钡薄膜的过程 ,膜层厚度可达 5 μm。通过X射线衍射、摇摆曲线、扫描、拉曼散射光谱等方法研究了薄膜的微结构性能 ,实验发现 ,铌酸锶钡薄膜具有了较好的 (0 0 1)方向的优先取向性能 ,并且随着薄膜厚度的增加 ,其晶体取向性也会随之不断改进。熔石英的透明衬底上生长的SBN薄膜具有较大的电致双折射效应 ,其有效电光系数能够高达 6 6 2× 10 -11m/V。     

在电光光学双稳中一种降低晶体半波电压的方法

本文采用非线性晶体调制函数曲线平移的计算方法和计算方程，并在实验上作了检证，绘制出电光晶体半波电压工作曲线、测试不同条件下的各种调制函数曲线和滞后回线。结果证明：电光晶体调制函数曲线平移法是一种有效制做非线性晶体半波电压Ｖｎ的光学方法。     

Effect of K-doping on structural and optical properties of ZnO thin films

In this work, K-doped ZnO thin films were prepared by a sol–gel method on Si(111) and glass substrates. The effect of different K-doping concentrations on structural and optical properties of the ZnO thin films was studied. The results showed that the 1 at.% K-doped ZnO thin film had the best crystallization quality and the strongest ultraviolet emission ability. When the concentration of K was above 1 at.%, the crystallization quality and ultraviolet emission ability dropped. For the K-doped ZnO thin films, there was not only ultraviolet emission, but also a blue emission signal in their photoluminescent spectra. The blue emission might be connected with K impurity or/and the intrinsic defects (Zn interstitial and Zn vacancy) of the ZnO thin films.     

高择优取向硅基含钾铌酸锶钡（K:SBN）薄膜的制备与性能

采用NbCl5作为先驱物，利用溶胶-凝胶法在Si(100)衬底上成功获得高度择优取向的铁电铌酸锶钡(SBN)薄膜.与用Nb(OC2H5)5作为先驱物的SBN薄膜相比，NbCl5配制的薄膜前驱溶液中含有一定数量的K离子.K离子的含量对SBN薄膜取向的影响存在一个最优值.二次离子质谱测试发现，K离子对SBN晶胞的溶入和对Si衬底的渗透能够同时使SBN晶胞和Si晶胞产生微小扭曲，从而起到调整薄膜与衬底的匹配关系，并最终促使SBN薄膜c轴高度择优取向的生长.测试了薄膜的光学特性. 关键词： 铌酸锶钡 溶胶-凝胶方法 择优取向     

铁电铌酸锶钡薄膜的结构特性研究

采用溶胶凝胶法在Si(001)基片上制备铁电铌酸锶钡薄膜,使用X射线衍射、摇摆曲线、扫描电子显微镜、喇曼散射光谱等测试手段研究薄膜的微结构与薄膜厚度之间的关系,制备的薄膜厚度可达到5μm.实验发现,随着薄膜厚度的增加,SBN60和SBN75薄膜在(001)方向的优先取向性越来越好.随着膜层的增加,处于底层的膜层能够起到缓冲层的作用,以逐渐改善薄膜与基片之间的晶格失配,从而使得晶体的结晶取向性越来越好.     

Transverse laser induced thermoelectric voltage effect in tilted La0.5Sr0.5CoO3 thin films

The transverse laser induced thermoelectric voltage effect has been investigated in tilted La_0.5Sr_0.5CoO₃ thin films grown on vicinal cut LaAlO₃ (1 0 0) substrates when films are irradiated by pulse laser at room temperature. The detected voltage signals are demonstrated to originate from the transverse Seebeck effect as the linear dependence of voltage on tilted angle in the range of small tilted angle. The Seebeck coefficient anisotropy ΔS of 0.03 μV/K at room temperature is calculated and its distorted cubic structure is thought to be responsible for this. Films grown on a series of substrates with different tilted angles show the optimum angle of 19.8° for the maximum voltage. Film thickness dependence of voltage has also been studied.     

Improvement of dielectric （Ba,Sr）TiO3 thin tunability and loss tangent of films with K doping

Ba0.6Sr0.4 TiO3 thin films doped with K were deposited on Pt/Ti/SiO2 /Si substrates by the chemical solution deposition method. The structure, surface morphology and the dielectric and tunable properties of Ba0.6Sr0.4 TiO 3 thin films have been studied in detail. The K content in Ba0.6Sr0.4TiO3 thin films has a strong influence on the material’s properties including surface morphology and the dielectric and tunable properties. It was found that the Curie temperature of K-doped Ba0.6Sr0.4 TiO3 films shifts to a higher value compared with that of undoped Ba0.6Sr0.4TiO3 thin films, which leads to a dielectric enhancement of K-doped Ba0.6Sr0.4 TiO3 films at room temperature. At the optimized content of 0.02 mol, the dielectric loss tangent is reduced significantly from 0.057 to 0.020. Meanwhile, the tunability is enhanced obviously from 26% to 48% at the measured frequency of 1 MHz and the maximum value of the figure of merit is 23.8. This suggests that such films have potential applications for tunable devices.