高品质因子聚合物波导微环谐振腔滤波器

基于紫外固化胶和聚砜聚合物材料体系,采用脊形单模波导结构,理论设计并优化了聚合物波导环形谐振腔滤波器的波导截面参数、弯曲半径和耦合区波导间距等结构参数,分析了其滤波响应特性.并在此基础上,结合光刻、反应离子刻蚀等传统的微加工工艺制备了聚合物环形谐振腔滤波器,并进行了光谱测试,器件测试结果与设计基本符合.结果表明,该聚合物微环谐振腔滤波器在通信波段1550 nm附近的自由光谱范围为0.21 nm,3 dB带宽为0.04 nm,插入损耗为26 dB,消光比达到了11 dB,品质因子达到了3.87×104.该聚合物微环谐振腔滤波器可以用于光通信及光传感集成芯片.     

芳杂环推拉型大分子的多光子上转换荧光性质

用Wittig反应和Heck反应制备了2个新的芳杂环推-拉型荧光大分子聚[(2,5-二苯撑-1,3,4-噁二唑)-4,4'-乙烯撑-交替-N,N'-二(4-苯乙烯撑)]苯胺(P1)和聚[(2,5-二苯撑-1,3,4-噁二唑)-4,4'-乙烯撑-交替-N-乙基-3,6-咔唑乙烯撑](P2). P1和P2的分解温度分别为373和412 ℃, 热稳定性良好. 电化学性能用循环伏安法测定. P1和P2的最高占有分子轨道(HOMO)能级分别为-5.39和-5.81 eV, 最低未占有分子轨道(LUMO)能级分别为-2.81和-3.09 eV. 用飞秒Ti:Sapphire激光器测定了P1和P2的三光子和双光子上转换荧光光谱. 在1250 nm波长激发下, 在四氢呋喃溶液中P1和P2的三光子荧光发射峰分别位于510和491 nm. 在800 nm波长激发下, 在四氢呋喃溶液中P1和P2的双光子荧光发射峰分别位于511和495 nm. 在四氢呋喃溶液中大分子P1和P2单光子荧光发射峰分别位于503 和475 nm, P1和P2的荧光量子产率分别为0.80和0.31. 研究了多光子荧光发射过程的溶剂效应. 结果表明, 溶剂极性增大, P1和P2的多光子荧光发射波长明显红移.     

Disc-Capped ZnO Nanocombs

Nanocombs with a disc cap structure of ZnO have been synthesized on Si substrates by using pure Zinc powaers as the source materials based on a vapour-phase transport process. The morphology and the microstructure are investigated by a scanning electron microscopy and x-ray diffraction. Based on the transmission electron microscopy and selected area electron diffraction analysis, the growth directions of three representative parts, nanoribbon stem, nanorod branch and nanodisc cap of the nanocomb are revealed. The growth mechanism of the disc-capped nanocombs is discussed based on the self-catalyzed vapour-liquid-solid process.     

PUT/SiO2复合材料的制备与表征

利用溶胶-凝胶法将硅烷染料、含硅氧烷的非线性聚氨酯与正硅酸乙酯(TEOS)共水解, 缩合制备了新型聚氨酯噻唑(PUT/SiO2)纳米复合材料, 并用IR、SEM、TEM、UV-Vis、DSC和TGA对其结构和性能进行了表征. 结果显示, 材料中聚氨酯与SiO2以共价键相连, 没有发生相分离, 且其中非线性较好的噻唑生色团含量和材料的玻璃化转变温度(Tg)、热分解温度(Td)都较纯非线性光学材料(NLO)聚氨酯(PU)有显著增加, 可以用来制备性能优良的二阶非线性光学器件.     

AπDπA型咔唑衍生物三阶光学非线性的Z-扫描研究

合成了6个新型AπDπA型3,6-二取代咔唑多极生色分子, 用红外光谱、核磁共振等对其结构进行了表征. 用Z-扫描方法研究了这些分子的三阶非线性光学性质. 实验结果表明, 这些分子具有较大的三阶极化率, 延长共轭链长度, 增加电子受体强度, 引入芳香杂环, 都能增强分子内电荷转移, 这种效应增加了分子的跃迁矩, 使三阶极化率增大.     

吡啶星型分子的双光子上转换荧光特性

用飞秒Ti:sapphire激光测定了一种星型吡啶分子2,5-二{4-{4-[N,N-二(4-吡啶乙烯基)苯基氨基]苯乙烯基}苯基}-1,3,4-噁二唑(PyPASPO)的双光子吸收截面及上转换荧光光谱.采用非线性透过率法测得二氯甲烷和四氢呋喃溶液中的其双光子吸收截面分别为412.5 和288.8 GM. 系统研究了吡啶星形分子PyPASPO的线性吸收和透过、单光子荧光、荧光寿命及激发-发射三维荧光谱和前线轨道能级. 在800 nm和150 fs钛宝石激光器激发下PyPASPO在二氯甲烷和四氢呋喃溶液中的双光子上转换荧光发射波长分别位于571和 525 nm,在二氯甲烷溶液中单光子荧光峰位于532 nm,荧光寿命为1.24 ns. HOMO和LUMO能级分别为-5.21 eV和-2.92 eV.增大分子内电荷转移有效增强了吡啶星形分子的双光子吸收和双光子上转换荧光发射能力     

Independent Modulation of Omnidirectional Defect Modes in Single-Negative Materials Photonic Crystal with Multiple Defects

Single-negative materials based on photonic crystal with multiple defect layers are designed and the free modulation of defect modes is studied. The results show that the multi-defect structure can avoid the interference between the defect states. Therefore, the designed double defect modes in the zero effective-phase gap can be adjusted independently by changing the thickness of different defect layers. In addition, the two tunable defect modes have the omnidirectional characteristics. This multi-defect structure with above-mentioned two advantages has potential applications in modern optical devices such as tunable omnidirectional filters.     

SECOND-ORDER NONLINEAR OPTICAL PROPERTIES OF TITANIUM DIOXIDE NANOPARTICLES AND NANOPARTICLES-DYE COMPOSITES

Hyper-Rayleigh Scattering (HRS) technique was used to study the second-order nonlinear optical (NLO) responses of aqueous titanium dioxide (TiO₂) nanoparticles of 10nm in size, and two nanoparticles-dye composites prepared by adding rhodamine B (Rh610) or the organic tosylate salt of dimethylaminostilbazolium (DAST). Results showed that the "per particle" first hyperpolarizability β for TiO₂ nanoparticles is very large, in the range of 10²⁶ esu. With adding Rh610 and DAST, the HRS signals of the composites were further enhanced. And in TiO₂/Rh610 composite the enhancement was obviously greater than that of TiO₂/DAST composite. It has proved that non-centrosymmetry of the nanocrystal/solution interface contributes mainly to its large "per particle" β, overwhelming the nanocrystal core. So the interactions between nanoparticles surfaces and adsorbed dyes were very important for their second-order NLO responses. HRS technique provides a useful new NLO method to characterize the surface structures and microenvironment of nanoscale materials.     

吡啶盐二维电荷转移分子的设计、合成和超级化氯的测定

设计、合成了以吡啶阳离子为吸电子基团的二维电荷转移非线性光学生色团分子－双四苯鹏(反式)-4,4'-二{p-[(N-乙基-N-羟乙基)氨基]苯亚乙烯基}-N,N'-(1,2-乙基)-2,2'-联吡啶盐和双四苯硼(反式)-N-己基-咔唑-3,6-二(p-亚乙烯基-N-羟乙基-吡啶盐),利用超瑞利散射技术(HRS)测定了这两种分子的第一超级化率β,在1064nm分别为786x10^-^3^0esu和1770x10^-^3^0esu。双能级模型计算得到的β0的值分别为215x10^-^3^0esu和119x10^-^3^0esu。从分子结构的角度定性地分析了该类分子具有大β值的原因。     

有机吡啶盐的电致发光

有机盐是一种离子化合物,其分子间依靠比范德瓦尔斯力大得多的离子键结合,这有利于器件稳定性的提高。主要研究一种以新型有机吡啶盐ASPT(trans-4-[P-(N-ethyl-N-(hydroxylethyl)-amino)styryl]-N-methylpyridinium tetraphenyl-borate)作发光层的有机电致发光特性。实验发现有机盐ASPT是一种性能较好的红光发射材料。利用ASPT作发光层的单层电致发光器件,可获得稳定的红色电致发光。通过对外场界面势垒影响分析,我们讨论了这种单层器件的发光机理。为了探索ASPT中载流子传输与复合过程,并提高器件性能,设计了ASPT/Alq₃双层和TPD/ASPT/Alq₃三层结构的器件,进一步研究了它们的光电特性。实验结果表明,利用双层器件可获得亮度较高的红色发光。而在三层器件中,由于不同功能层的载流子传输特性的差别,激发复合区域受到驱动电压的显著影响,因此电致发光光谱随电压的变化而变化。通过对光谱结构、能级位置的分析,讨论了相关的发光机理。