掺铒磷酸盐玻璃离子交换波导表面保护的研究

对离子交换波导制备过程中掺铒磷酸盐玻璃表面的侵蚀问题进行了研究，分析了产生侵蚀的原因，提出镀K9玻璃薄膜的方法，对掺铒磷酸盐玻璃表面进行保护．采用光学显微镜和原子力显微镜对波导表面特性进行了表征。同时对平板波导的光学特性进行了测试．研究表明K9玻璃薄膜不仅能够对掺铒磷酸盐玻璃起到保护作用，同时允许交换离子透过进入磷酸盐玻璃形成波导层．

K9玻璃薄膜对离子交换磷酸盐玻璃波导表面保护的优化研究

采用镀K9玻璃薄膜方法来解决离子交换掺铒磷酸盐玻璃波导表面的侵蚀问题,对K9玻璃薄膜的厚度进行了优化研究。测量分析了样品的荧光光谱和荧光寿命,采用光学显微镜和棱镜耦合技术对不同K9玻璃薄膜厚度下制备波导的表面形貌和导光特性进行了表征和测试。结果表明,与掺铒磷酸盐玻璃原材料相比,镀K9玻璃薄膜后荧光光谱保持不变,荧光寿命稍有下降(约0.2 ms);K9玻璃薄膜的厚度在60~80 nm的范围内保护效果最佳。为下一步制备掺铒有源玻璃光波导器件奠定了良好的实验基础。

I. Fundamental limitations in microelectronics. II. Power Schottky diode design and comparison with the junction diode. III. Permittivity of strontium titanate

Part I

The physical phenomena which will ultimately limit the packing density of planar bipolar and MOS integrated circuits are examined. The maximum packing density is obtained by minimizing the supply voltage and the size of the devices. The minimum size of a bipolar transistor is determined by junction breakdown, punch-through and doping fluctuations. The minimum size of a MOS transistor is determined by gate oxide breakdown and drain-source punch-through. The packing density of fully active bipolar or static non-complementary MOS circuits becomes limited by power dissipation. The packing density of circuits which are not fully active such as read-only memories, becomes limited by the area occupied by the devices, and the frequency is limited by the circuit time constants and by metal migration. The packing density of fully active dynamic or complementary MOS circuits is limited by the area occupied by the devices, and the frequency is limited by power dissipation and metal migration. It is concluded that read-only memories will reach approximately the same performance and packing density with MOS and bipolar technologies, while fully active circuits will reach the highest levels of integration with dynamic MOS or complementary MOS technologies.

Part II

Because the Schottky diode is a one-carrier device, it has both advantages and disadvantages with respect to the junction diode which is a two-carrier device. The advantage is that there are practically no excess minority carriers which must be swept out before the diode blocks current in the reverse direction, i.e. a much faster recovery time. The disadvantage of the Schottky diode is that for a high voltage device it is not possible to use conductivity modulation as in the p i n diode; since charge carriers are of one sign, no charge cancellation can occur and current becomes space charge limited. The Schottky diode design is developed in Section 2 and the characteristics of an optimally designed silicon Schottky diode are summarized in Fig. 9. Design criteria and quantitative comparison of junction and Schottky diodes is given in Table 1 and Fig. 10. Although somewhat approximate, the treatment allows a systematic quantitative comparison of the devices for any given application.

Part III

We interpret measurements of permittivity of perovskite strontium titanate as a function of orientation, temperature, electric field and frequency performed by Dr. Richard Neville. The free energy of the crystal is calculated as a function of polarization. The Curie-Weiss law and the LST relation are verified. A generalized LST relation is used to calculate the permittivity of strontium titanate from zero to optic frequencies. Two active optic modes are important. The lower frequency mode is attributed mainly to motion of the strontium ions with respect to the rest of the lattice, while the higher frequency active mode is attributed to motion of the titanium ions with respect to the oxygen lattice. An anomalous resonance which multi-domain strontium titanate crystals exhibit below 65°K is described and a plausible mechanism which explains the phenomenon is presented.

Isotope shift studies in the rare earths and lead

Isotope shifts of K_α1 x-ray transitions were measured for the Neodymium isotopes Nd 142, 143, 144, 145, 146, 148 and 150, the Samarium isotopes Sm 147, 148, 149, 150, 152 and 154, the Gadolinium isotopes Gd 154, 155, 156, 157, 158 and 160, the Dysprosium isotopes Dy 162 and 164, the Erbium isotopes Er 166, 168 and 170, the Hafnium isotopes Hf 178 and 180 and the Lead isotopes Pb 204, 206, 207 and 208. A curved crystal Cauchois spectrometer was used. The analysis of the measurement furnished the variation of the mean square charge radius of the nucleus, δ˂r²˃, for 23 isotope pairs. The experimental results were compared with theoretical values from nuclear models. Combining the x-ray shifts and the optical shifts in Nd and Sm yielded the optical mass shifts. An anomaly was observed in the odd-even shifts when the optical and the x-ray shifts were plotted against each other.

掺镱双包层光纤放大器高功率脉冲放大特性

从放大器速率方程出发，分析了掺镱双包层光纤放大器的放大特性。模拟计算了无信号输入时放大器上能级粒子数、泵浦功率和放大自发辐射（ASE）在放大器中的稳态分布。分析了前向和后向泵浦时，高功率高斯脉冲放大时的脉冲波形畸变、上能级粒子数的时间特性、放大器存储能量和脉冲能量演化等动态特性。讨论了掺镱双包层光纤放大器输出脉冲能量随不同输入脉冲峰值功率和泵浦功率的关系。该模型和结论对高功率脉冲放大器的设计和优化具有一定的理论指导意义。

Propriedades ópticas, magnéticas e estruturais de monocristais Cs2NaAlF6 dopados com cromo trivalente

Este trabalho teve por objetivo a realização do estudo das propriedades ópticas, magnéticas e estruturais do cristal elpasolita Cs2NaAlF6 dopado com as concentrações de 0,1%, 1,0%, 3,0%, 10,0%, 30,0% e 50,0% de Cr3+. O interesse no estudo deste sistema reside na existência de uma larga e intensa banda de luminescência na temperatura ambiente, que se estende do visível ao infravermelho próximo, podendo então ser utilizado como fonte de radiação sintonizável em dispositivos ópticos, optoeletrônicos e detectores, entre outros. Para a investigação das propriedades ópticas foram feitas medidas de luminescência, excitação e luminescência resolvida no tempo, na temperatura ambiente e a baixas temperaturas. Os resultados obtidos mostram largas bandas de luminescência atribuídas aos íons de Cr3+, ocupando dois sítios octaédricos não equivalentes. Os resultados também mostram que a intensidade integrada da luminescência, o baricentro da banda de emissão e o tempo de vida do estado luminescente variam com a concentração de impureza residente no sistema. Foram realizadas medidas de calor específico em função do campo magnético em uma larga faixa de temperatura, cujos resultados mostram o aparecimento do efeito Schottky a baixas temperaturas. Medidas de susceptibilidade magnética em funcão da temperatura também foram realizadas, e mostram um comportamento paramagnético, típico do íon impureza Cr3+, com um ordenamento magnético de curto alcance. Para a determinação das propriedades estruturais foram realizadas medidas de difração de nêutrons na temperatura ambiente.

基于高频微波技术的分布式光纤传感器布里渊散射信号检测

分析了布里渊分布式光纤传感技术原理,采用自行研制的光纤单纵模分布反馈(DFB)激光器结合电光调制技术,利用相干检测技术,对布里渊微弱后向散射信号进行检测。通过改进滤波放大技术,对微弱后向散射光信号进行有效放大,再用扰偏技术及信号采样平均处理,实现对光纤传感器后向布里渊散射信号在11 GHz高频段直接采集显示。结果表明,探测所得布里渊散射信号峰值功率可达50 mV,能有效降低解调系统信号检测难度,改善了系统信噪比(SNR)。初步实验结果证明了该方案的可行性。

一种利用相位掩模版对光栅波长进行微调的光栅刻写方法

提出并实验证实了一种刻写光栅时既能保护相位版又能对光栅的反射波长进行微调的方法．通过调整光纤和相位版之间的距离，利用1550nm单模光纤和掺铒分别实现了0．48nm和2．2nm的光栅反射波长的调节．在相位版和光纤之间的距离保持在3mm的条件下，既可以保护相位版又可以获得高质量的光栅．

Strong visible up-conversion emissions and thermometric applications of Er3+-Yb3+ codoped Al2O3 prepared by the sol-gel method

The Er3+-Yb3+ codoped Al2O3 has been prepared by the sol-gel method using the aluminium isopropoxide [Al(OC3H7)(3)]-derived Al2O3 sols with addition of the erbium nitrate [Er(NO3)(3) center dot 5H(2)O] and ytterbium nitrate [Yb(NO3)(3) center dot 5H(2)O]. The phase structure, including only two crystalline types of doped Al2O3 phases, theta and gamma, was obtained for the 1 mol% Er3+ and 5 mol% Yb3+ codoped Al2O3 at the sintering temperature of 1,273 K. By a 978 nm semiconductor laser diodes excitation, the visible up-conversion emissions centered at about 523, 545, and 660 nm were obtained. The temperature dependence of the green up-conversion emissions was studied over a wide temperature range of 300-825 K, and the reasonable agreement between the calculated temperature by the fluorescence intensity ratio (FIR) theory and the measured temperature proved that Er3+-Yb3+ codoped Al2O3 plays an important role in the application of high temperature sensor.

Effect of the A cation size disorder and synthesis conditions on the properties of an iron perovskite series

Póster presentado en The Energy and Materials Research Conference - EMR2015 celebrado en Madrid (España) entre el 25-27 de febrero de 2015

Optimization of the pyrolysis process for the production of a biomass derived reducing agent and hydrogen-rich gases

221 p.

Write-once blue laser recording using silicon doped SbOx thin films prepared by reactive dc-magnetron sputtering

Si:SbOx films have been deposited by reactive dc-magnetron sputtering from a Sb target with Si chips attached in Ar + O-2 with the relative O-2 content 7%. The as-deposited films contained Sb metal, Sb2O3, SiO, Si2O3 and SiO2. The crystallization of Sb was responsible for the changes of optical properties of the films. The results of the blue laser recording test showed that the films had good writing sensitivity for blue laser beam (406.7 nm), and the recording marks were still clear even if the films were deposited in air 60 days, which demonstrated that doping silicon in SbOx films can improve the stability of SbOx films. High reflectivity contrast of about 36% was obtained at a writing power 6 mW and writing pulse width 300 ns. (c) 2007 Elsevier B.V. All rights reserved.

氧化物记录介质在光存储中的应用及其研究进展

系统总结了用于光存储记录层的氧化物薄膜的存储机理、存储特性以及最新进展，讨论了氧化物掺杂对提高存储性能的影响，指出了氧化物薄膜存在的不足，并探讨了可能的改善途径。在此基础上对存储材料的发展趋势及氧化物材料的研究前景进行了展望。

Influence of synthetic method on the properties of La0.5Ba0.5FeO3 SOFC cathode

Power Point presentado en The Energy and Materials Research Conference - EMR2015 celebrado en Madrid (España) entre el 25-27 de febrero de 2015

Output beam quality of edge pumped planar waveguide lasers with confocal unstable resonators

Output beam quality of edge pumped planar waveguide lasers with confocal unstable resonators is investigated by diffraction methods, taking into account gain saturation, asymmetric pumping, and beam interaction. The influences of pumping uniformity, doping concentration, cavity length and effective Fresnel number are analyzed with respect to output beam quality and pumping efficiency. It is found that good beam quality and high efficiency can be obtained with asymmetric pumping and optimized negative branch confocal unstable resonators. (c) 2005 The Optical Society of Japan.