挥发速率对胶体悬浮液干燥花样的影响

研究了不同挥发速率下厚度较薄的凹液层胶体悬浮液的干燥花样。Panasonic照相机用于拍摄宏观干燥花样。结果表明,随着挥发速率的减小,马兰哥尼对流强度下降,胶体悬浮液的干燥花样更为平整均匀。在较低的挥发速率下可避免宽环花样形成,制备得到表面平整的薄膜,反射光谱证明其可作为三维光子晶体材料。     

不同胶晶模板制备3DOM材料及结构色剂应用的研究进展

结构色因饱和度高、虹彩效应、附着力好、耐刮擦和环境友好性而受到广泛关注。3DOM材料具有独特的反蛋白石结构和完全光子禁带,因而是制备结构色剂的潜在材料。综述了模板法制备3DOM材料的研究进展以及它在结构色剂领域的应用前景。详细评述了胶晶模板法中聚苯乙烯(PS)、聚甲基丙烯酸甲酯(PMMA)和二氧化硅为模板的差别。最后展望了3DOM材料的努力方向和发展前景。     

CdSe-SiO2光子晶体的垂直沉积及近红外变频特性

在氧化铟锡玻璃上电化学合成了CdSe薄膜,采用垂直沉积法首次在CdSe薄膜上制备了SiO2胶体晶体, 实现了CdSe表面介电常数的调节.扫描电镜观察表明,500nm微球在CdSe薄膜上呈面心立方密堆结构排列,在微米尺度上胶体晶体显示出一定的多晶序.与SiO2胶体晶体相比,CdSe-SiO2光子晶体的UV-vis-NIR透射谱只有一个较宽的光子带隙,带隙在近红外波段随入射角减小向短波方向移动.所得CdSe-SiO2光子晶体样品可作为地面目标针对红外卫星成像的伪装材料.     

Ultra-bandwidth polarization splitter based on soft glass dual-core photonic crystal fiber

A novel ultra-bandwidth polarization splitter based on soft glass dual-core photonic crystal fiber (DC-PCF) is designed in this paper, which is analyzed through the finite element method (FEM). The coupling characteristics of the designed DC-PCF can be enhanced by a high refractive index As₂S₃ core. Numerical results show the ultra-bandwidths of the x- and y-polarization modes can reach to 86 nm and 60 nm as the extinction ratios better than −20 dB and −30 dB at the vicinity of the wavelength of 1.31 μm. The length of the designed soft glass DC-PCF is 52.29 mm and the extinction ratios of the x- and y-polarization modes are −85.57 dB and −56.81 dB at the wavelength of 1.31 μm, respectively. In addition, the designed splitter has a tolerance of ±10 nm in its all structure parameters, which make the design not sensitive to the perturbation during the fabrication process.     

光子晶体用二氧化硅胶体球的改性制备及其自组装

采用一步法制备了表面接枝甲基丙烯酰氧基三甲氧基硅烷(MPS)的单分散SiO2胶体球,并通过垂直沉积法在40℃、60%相对湿度下组装出有序性较好的密排结构的SiO2光子晶体.傅立叶红外光谱(FT-IR)和X射线光电子能谱(XPS)结果证明SiO2胶体球表面接枝上了MPS;扫描电子显微镜(SEM)结果表明改性后SiO2胶体球平均粒径为284nm,单分散性较高,平均标准偏差＜5%;制备出的光子晶体是面心立方(fcc)紧密堆积结构;吸收光谱表明,所制备的光子晶体在(111)方向具有光子晶体的带隙特性,带隙中心波长为646nm.     

High contrast glasses for all-solid fibers fabrication

We present composition development of borosilicate glasses for fabrication of high refractive index contrast, all-solid photonic crystal fibers. An oxide system composed of SiO₂B₂O₃Al₂O₃Li₂ONa₂OK₂O was adjusted to match thermal properties of selected highly nonlinear, lead bismuth gallium silicate glass. A high difference of refractive index of 0.376 is achieved at a wavelength of 1550 nm. We proved experimentally that the developed pair of glasses enables to draw optical fibers, and we propose a design of a photonic crystal fiber structure for broadband supercontinuum generation.     

高压均质技术对低熔点玻璃粉的细化及烧结性能的影响

利用羧甲基纤维素(CMC)作为低熔点玻璃粉水分散液的防沉剂, 用高压均质机对玻璃粉进行细化处理, 使其粒度减小. 探讨了不同高压均质时间对玻璃粉的粒度大小和烧结性能的影响; 结果表明: 在相同的压强下(50 MPa), 高压均质时间越长则玻璃粉粒度越小、粒度分布范围越窄, 其软化温度和烧结温度也越低. 因此可以利用高压均质技术来降低玻璃粉的粒度, 从而降低玻璃粉的软化温度和烧结温度.     

二氧化硅胶体晶体的制备及其光子带隙特性

利用胶体颗粒悬浊液的自组织生长技术制备了两种二氧化硅胶体晶体．透射光谱表明：所制备的胶体晶体的光子带隙位于近红外波段,带隙的位置随胶体晶体中胶粒的尺寸而变化;且放置时间延长,带隙将发生蓝移．     

Thermal properties and two-dimensional photonic band gaps

The effect of temperature on a two-dimensional square lattice photonic crystal composed of Si rods arranged in an air background was investigated theoretically using the plane-wave expansion method. Both the thermal expansion effect and thermo-optical effect are considered simultaneously. We have discussed the role of temperature in creating the complete photonic band gap as a function of temperature. Two different shapes of rods, i.e. square and circular, are considered in the presence of the two polarization states, i.e. TE and TM waves. The numerical results show that the photonic band gap can be significantly enlarged compared to the photonic band gap at room temperature. The effect of temperature on the complete photonic band width in the cylindrical rods case is more significant. Cylindrical and square Si rods may work as a temperature sensor or filter, among many other potential applications.     

带隙可调光子晶体的研究进展

介绍了近几年带隙可调光子晶体的研究进展。带隙调节的机制主要有改变晶体材料的平均折射率和改变晶体的结构参数两种。综述了通过电场调制、磁场调制、压力调制、光照调制、温度调制和复合调制等实现带隙实时可调的研究进展,提出了目前存在的问题及研究方向。