硅化铂肖特基势垒红外焦平面列阵及其发展

介绍PtSi肖特基势垒红外焦平面列阵的工作原理,分析探测器的最佳化结构,评述国内外肖特基势垒红外焦平面列阵的发展。     

Non-contact optical fibre phased array generation of ultrasound for non-destructive evaluation of materials and processes

The use of non-contact laser techniques for the generation of ultrasound has extended the limits of the application of traditional ultrasonic techniques. This paper focusses on the use of one such non-contact laser technique, known as ‘optical fibre array’, to generate shear and surface waves. The shear wave experimental directivity pattern results are presented and compared with the theoretical results of a single source and an array source. The experimental directivity results for the surface wave are also presented, and compared with the theoretical results. The data show that the array enhances signal generation in the forward direction for both shear and surface waves. The array gain is also discussed. The receiver for the directivity measurements was a contact piezoelectric transducer.     

Ti：LiNbO3光波导导模的场分布

给出了Ti扩散LiNbO_3条波导任意阶导模场分布的试探解.通过变分法分析,不但可以合理地确定其中的待定参数,而且也得到了相应导模传播常数的近似值.与扩展的有效折射率方法比较:这种解不但在函数形式上简单,待定常数确定方便,而且具有精度高的优点.还可以得到等效一维波导折射率分布的解析表达式.     

足球烯分子C_(60)及C_(70)的反饱和吸收性质与光限制效应

报道了对足球烯分子纯C_60及纯C_70的光限制效应的研究结果,讨论了样品的浓度及三重态寿命对光限制阈值的影响.首次报道在足球稀分子中发现的三重态吸收饱和现象,并阐述了其产生的原因及对光限制效应的影响.     

足球烯分子三阶非线性光学性质的研究

报道了有关足球烯分子甲苯溶液中简并四波混频实验.测量出足球烯C_(70)分子和C_(60)分子的三阶超极化率张量y_(1111)分量分别为1.2×10~(-30)esu和4.0×10~(-31)esu.对应于固体样品的三阶非线性光学系数X_(1111)分量分别是2.5×10~(-8)esu和8.5×10~(-9)esu.此结果表明了足球烯分子是现有的非线性光学材料中具有较大三阶非共振电子极化率材料之一.文中还利用自由电子模型解释了非线性光学极化率的起源.     

二次型复折射率介质中的光导现象

本文讨论了n(z,r)=n_0(z)+n_2(z)r~2/r_e~2型复折射率介质中的激光传输问题,给出了激光传输参数(光束半径和波阵面曲率)的演化公式。指出只要存在一定大小的n_(21),在传输过一段特征距离z_c之后,将出现完全光导(即自相似模的传播),而且自相似模是激光体系的特征模式。其传输参数只与n_2有关,而与激光初始参数无关。自相似模必定是高斯球面波,而不是高斯平面波。     

A scanning tunneling microscopy study of PH3 adsorption on Si(1 1 1)-7 × 7 surfaces, P-segregation and thermal desorption

PH₃ adsorption on Si(1 1 1)-7 × 7 was studied after various exposures between 0.3 and 60 L at room temperature by means of scanning tunneling microscopy (STM). PH₃-, PH₂-, H-reacted, and unreacted adatoms can be identified by analyzing empty-state STM images at different sample biases. PH_x-reacted rest-atoms can be observed in empty-state STM images if neighboring adatoms are hydrogen terminated. Most of the PH₃ adsorbs dissociatively on the surface, generating H- and PH₂-adsorbed rest-atom and adatom sites. Dangling-bonds at rest-atom sites are more reactive than adatom sites and the faulted half of the 7 × 7 unit cell is more reactive than the unfaulted half. Center adatoms are overwhelmingly preferred over corner adatoms for PH₂ adsorption. The saturation P coverage is ∼0.18 ML. Annealing of PH₃-reacted 7 × 7 surfaces at 900 K generates disordered, partially P-covered surfaces, but dosing PH₃ at 900 K forms P/Si(1 1 1)- surfaces. Si deposition at 510 K leaves disordered clusters on the surface, which cannot be reordered by annealing up to 800 K. However, annealing above 900 K recreates P/Si(1 1 1)- surfaces. Surface morphologies formed by sequential rapid thermal annealing are also presented.     

液晶染料填充阶梯型Double-period结构局域模的光学特性

利用传输矩阵法研究了液晶染料填充一维阶梯型Double-period第四代准周期结构局域模的光学特性。计算了增益前局域模与外加电场方向和正入射波方向间夹角θ的变化关系,分析了增益系数与局域模透射率的关系以及局域模在空间位置的光场分布,讨论了增益后的局域模透射率与光场强度的关系。结果表明:随着夹角θ的增大,光子禁带变宽并且只向短波方向拓展;随着夹角θ的增大,增益前的局域模向短波方向移动,透射率逐渐增大,且局域模波长的调控量为23.7nm。随着增益系数的增大,透射率先增大后减小。光场分布呈现局域现象,当夹角θ=43.4°,波长λ=595.0nm时,光强达到6个数量级。增益后的局域模透射率与光场强度呈正比关系。     

基于荧光玻璃的高效LED白光技术

采用高温熔融法制备了一定质量比例的SiO_2-YAG∶Ce~(3+)片状荧光玻璃,厚度为0.2 mm,分析其XRD物相、光学和SEM微观结构、PL光谱。结果表明:荧光玻璃保留了晶相,荧光粉颗粒在玻璃基质中均匀分布,荧光玻璃和荧光粉的激发响应关系一致。在465 nm蓝光激发下,发射波长均在535 nm附近,表明荧光玻璃除含有玻璃相,还有荧光粉的物质结构特性。将不同波长蓝光芯片与不同荧光粉含量的荧光玻璃进行封装测试,结果表明:器件的流明效率可达到234.81 lm/W;色温和显色指数均随荧光粉含量增加而单调下降,呈现高色温和低显色指数;荧光粉质量分数从6%增加至15%时,不同波长激发下的色坐标x与y呈现大致相同的线性变化率。采用450 nm激光激发荧光玻璃,测试样品温度变化发现温升较缓,温降迅速,耐热性能优越。实验结果表明,将荧光玻璃用于LED白光照明封装,能实现流明效率和耐热性能的大幅提升,形成良好的白光输出。     

溶剂热法制备铜锌锡硫粉末及光学性能研究

以金属氯化物作为金属源,硫脲为硫源,乙二醇为溶剂,聚乙烯吡咯烷酮(PVP)为表面活性剂,采用溶剂热法在较低反应温度下合成了Cu2ZnSnS4(CZTS)粉末。利用X射线衍射仪(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)对样品的结构和形貌进行表征。利用紫外-可见光谱(UV-Vis)对样品的光学性能进行研究。结果表明,180℃反应25小时的样品均为锌黄锡矿CZTS颗粒,颗粒形貌为表面花状的微球。当体系中PVP含量为0.2g时,微球尺寸约为2.5μm。当体系中PVP含量为0.3g,0.4g,0.5g时,微球尺寸大约为1.1μm。其中,PVP含量为0.4g的样品分散性较好,在可见区有明显的吸收,用外延法得到其禁带宽度约为1.45eV,与太阳能电池所需的最佳禁带宽度接近。