双层单负材料结构的古斯-亨兴位移调控

运用反射相位法和高斯光束峰值位移判断法研究了由电单负材料(ENM)和磁单负材料(MNM)组成的双层结构的古斯-亨兴位移现象.首先利用传输矩阵计算结构的反射系数,通过对反射系数的相位分析,发现对于单层的电单负材料和单层的磁单负材料,反射高斯光束的古斯-亨兴位移方向相反,同时位移的大小与材料厚度存在一定的联系.进一步对双层...     

概率波的古斯-汉森位移

概率波在传输过程中很多性质可以与电磁波进行类比,电磁波入射至两种介质的交界面上发生全反射时会产生古斯-汉森位移,概率波在穿透势垒时也有类似的古斯-汉森位移现象,本文推导了概率波穿透方势垒时的古斯-汉森位移表达式,并讨论了该位移与入射角、势垒宽度、粒子能量等参量之间的关系.     

基于古斯-汉欣位移效应的波长传感研究

利用双面金属包覆波导在导模共振激发时对古斯-汉欣位移具有极大的增强效应来实现激光波长微小变化的监测.双面金属包覆波导由上层金膜、导波层和下层金膜组成.当导波层厚度为亚毫米尺度时,应用自由空间耦合技术使入射的激光以小角度入射,在满足相位匹配的条件下激发超高阶导模.理论研究表明,当波导的辐射损耗等于本征损耗时,反射光的侧向位移可达到数百微米,并且此时激发的超高阶导模对波长具有极强的色散能力.通过测量反射光的侧向位移可实现对激光波长变化的实时探测,且具有很高的灵敏度.同时,实验中探测信号只与光束位置相关,可有效避免因光源输出光强的波动带来的干扰.实验测量结果表明对激光波长在859nm附近的分辨率可达到0.2 pm.     

基于古斯-汉欣位移效应的波长传感研究

利用双面金属包覆波导在导模共振激发时对古斯-汉欣位移具有极大的增强效应来实现激光波长微小变化的监测.双面金属包覆波导由上层金膜、导波层和下层金膜组成.当导波层厚度为亚毫米尺度时,应用自由空间耦合技术使入射的激光以小角度入射,在满足相位匹配的条件下激发超高阶导模.理论研究表明,当波导的辐射损耗等于本征损耗时,反射光的侧向...     

棱镜-薄膜耦合结构中光束Goos-H(a)nchen位移的增强

棱镜-薄膜耦合结构是单侧镀电介质膜的双棱镜结构中的一种,在光信号传输方面具有十分重要的作用.利用稳态相位法分析了这种结构中反射和透射光束的Goos-Hanchen位移,研究结果表明,反射和透射光束的Goos-Hanchen位移随薄膜厚度或入射角的增大除出现共振峰外,还存在反射光束的Goos-Hanchen位移共振峰为负值的新现象.在共振点处透射和反射光束的正向或负向位移量最大可达百余波长.这一结构中薄膜和入射角.对光束Goos-Hanchen位移的调制在设计新型光位移调制和光传感器件中具有潜在的应用.     

影栅云纹法中的离面位移与斜率耦合条纹的光力学分析

基于传统的概念,影栅云纹法只能实时获得表征物体大离面位移(深度)的条纹。若要获得反映斜率的条纹,则只有用镜面试件通过反射云纹法或其它的光测法来获得。在研究中发现,在一定的条件下,用影栅云纹法可以获得离面位移与斜率的耦合条纹图。这个新发现打破了已有的传统概念。实验证实了简单实用的影栅云纹法不但能获得物体大变形时的离面位移,而且也可以获得与之对应的斜率条纹。给出了典型的可实时获得的耦合条纹图,并对其基本原理、计算方法和实验技术进行了论述。     

Micromagnetic and Magnetooptical Properties of Ferromagnetic/Heavy Metal Thin Film Structures

Physics of the Solid State - The magnetic properties of CoPt, CoPd, and FePd thin films with different contents of a ferromagnetic material fabricated by electron beam evaporation have been...     

负载型聚酰亚胺/SnO2杂化膜的结构和性能

通过溶胶凝胶法， 以硅藻土-莫来石陶瓷膜管为支撑体，TiO2为过渡层， 利用具有大量支链的聚酰亚胺和SnO2溶胶制备了系列不同SnO2含量的负载型聚酰亚胺/SnO2杂化膜．采用TEM、FTIR、XPS、TG/DTA、DSC、BET和气体渗透测定对系列膜的微观型态、化学结构、热稳定性、孔结构和气体渗透性能进行了表征和测试． 结果表明，SnO2相与聚酰亚胺支链羧酸基发生化学键连； 杂化膜具有较好的有机无机兼容性， 当SnO2达到15%时，SnO2相在杂化膜中以颗粒状存在， 其粒径约为5 nm；SnO2相与聚酰亚胺间的化学键连有效的提高了杂化膜的玻璃化温度； 随着SnO2含量的增加， 杂化膜的热分解温度逐渐下降； 系列膜具有均匀的孔道结构， 其孔径分别为3.8、3.1、2.8和2.4 nm． 相对于聚酰亚胺膜， 杂化膜对H2、CO2、CO和H2O具有较高的分离性，SnO2为15%的杂化膜对H2/N2、CO2/N2、CO/N2和H2O/N2的分离因子分别达到54.1、30.2、35.9和40.1．     

纳秒单脉冲激光诱导AgInSbTe薄膜的相变特性

利用磁控溅射法在K9玻璃基底上制备了Ag8In14Sb55Te23(AIST)纳米薄膜,并利用激光抽运-探测技术测量了薄膜的时间分辨反射率变化特性。研究结果表明,在合适能量密度的单脉冲纳秒激光脉冲作用下,AIST薄膜可以快速从沉积非晶态转化为晶态结构,晶化过程包含中间熔化态。在较低能量密度范围内,反射率变化量和晶化时间都随能量密度变化呈线性增加趋势。     

Compound Phase Formation in Thin Film Structures

Thin film compound formation during solid phase reaction, reactive deposition, ion-beam synthesis, and ion beam mixing is discussed in terms of the Effective Heat of Formation (EHF) model. This model defines an effective heat of formation ΔH′, which is concentration dependent. By choosing the effective concentration of the interacting species at the growth interface during solid phase reaction, to be that of the liquidus minimum, the model correctly predicts first phase formation during formation of silicides, germanides, aluminides, and other metal-metal binary systems. The ability to predict phase formation sequence and phase decomposition is also illustrated. The EHF model is also used to describe amorphous and metastable phase formation as well as the effect of impurities and diffusion barriers on phase formation. In the case of reactive deposition, the effective concentration is controlled by the rate at which thin film deposition is carried out and the temperature of the substrate. In this way epitaxial phases such as CoSi₂ and NiSi₂ can be formed directly at temperatures much lower than normally needed during solid phase reaction. During ion-beam synthesis silicon-rich compounds are expected to form during metal implantation into silicon- and metal-rich compounds for silicon implantation into a metal substrate. For ion-beam mixing, the effective concentration is not controlled by the mixing process at low temperatures, but by the liquidus minimum of the system at higher temperatures. For both ion-beam mixing and ion-beam synthesis, however, much work still needs to be done to correlate effective concentration with the various experimental parameters. The general trends of compound formation in these systems do, however, also correlate well with the predictions of the EHF model.     

脉冲溅射功率对含硅量子点SiC_x薄膜的结构和光学特性的影响

采用射频和脉冲磁控共溅射法并结合快速光热退火法制备了含硅量子点的SiC_x薄膜.采用掠入射X射线衍射、喇曼光谱、紫外-可见-近红外分光光度计和透射电子显微镜对薄膜进行表征.研究了脉冲溅射功率对薄膜中硅量子点数量、尺寸、晶化率和薄膜光学带隙的影响.结果表明:当溅射功率从70 W增至100 W时,硅量子点数量增多,尺寸增至5.33nm,晶化率增至68.67%,而光学带隙则减至1.62eV;随着溅射功率进一步增至110 W时,硅量子点数量减少,尺寸减至5.12nm,晶化率降至55.13%,而光学带隙却增至2.23eV.在本实验条件下,最佳溅射功率为100 W.     

Flexoelectric-Induced Voltage Shift in Hybrid Aligned Nematic Liquid Crystal Cell

Flexoelectric-induced voltage shift in a weak anchoring hybrid aligned nematic liquid crystal cell is investigated theoretically. Based on the elastic theory of liquid crystal and the variation method, the equations for the bulk and the boundary of the cell are derived. By computer simulation, the dependence of the
shift voltage on the sum of the flexoelectric coefficients and the anchoring energy strength is obtained. As a result, a novel method to determine the sum of the flexoelectric coefficients by measuring the shift voltage is put forward.