铌酸钾钠基1-3型压电复合物的制备及其性能研究

采用传统固相法制备了在1 130℃下烧结而成的(K_0.45Na_0.55)_0.98Li_0.02(Nb_0.77Ta_0.18Sb_0.05)O₃(KNLNTS)无铅压电陶瓷。陶瓷致密度和电学性能较好,致密度达到98%,室温压电常数为308.7 pC/N,厚度振动机电耦合系数可达0.5,1 kHz时介电损耗为0.043。以上述KNLNTS基粉体为原料,利用切割填充法制备1-3型压电复合材料并研究了厚度对复合材料的性能影响。结果表明,复合材料的压电常数、厚度振动机电耦合系数均随厚度的增加而增加,介电损耗随厚度的增加而减少,而相对介电常数基本保持不变。     

1-3型压电复合材料的机电响应特性和温度稳定性

1-3型压电复合材料具备优异的机电耦合性能,这对于高性能压电换能器的开发具有重要意义。该文采用低成本的切割填充法制备了不同结构参数的1-3型PZT/环氧树脂复合材料,并结合有限元模拟法对其压电性能、机电响应特性和温度稳定性进行了系统地研究。1-3阵列结构对平面方向应变产生了很大的衰减,使能量更集中于厚度共振模式。复合材料的高径比是影响机电耦合性能的主要因素,更精细的阵列结构有利于高性能压电换能器的制造。在-20～60℃内,1-3型压电复合材料的厚度机电耦合系数约为0.61,变化率小于1%,表现出良好的温度稳定性。     

近地大气532 nm激光散射的实验与计算

通过实验测出532 nm激光在近地大气的角散射系数,对Junge和Deirmendjian两种模型的气溶胶系统在不同的系统参数、不同的折射率的情况下的散射相函数进行了计算,发现与实验所测得的曲线有明显的差异,这两种模型都不存在散射次极峰.通过对不同半径粒子的散射相函数的计算,说明实验所测的气溶胶系统在粒子尺寸较大的区间的密度要比Junge和Deirmendjian两种模型的密度要大得多,在假定大粒子服从正态分布的前提下,拟合出了气溶胶的分布函数.     

Near-field lithography on the azobenzene polymer liquid crystal films

In this article, we reported near-field research on azobenzene polymer liquid crystal films using scanning near-field optical microscopy (SNOM). Optical writing and subsequently topographic reading of the patterns with subwavelength resolution were carried out in our experiments. Nanometer scale dots and lines were successfully fabricated on the films and the smallest dot diameter is about 120 nm. The width of the line fabricated is about 250 nm. This method is also a choice for nanolithography. The mechanism of the surface deformation on the polymer films was briefly analyzed from the viewpoint of gradient force in the optical near field. The intensity distribution of the electric field near the tip aperture was numerically simulated using finite-difference time-domain (FDTD) method and the numerical simulation results were consistent with the experimental results.     

表面等离子体亚波长光学前沿进展

目前表面等离子体激元(surface plasmon polaritons，SPPs)在光存储、光激发、显微术以及生物光子学等领域中的应用前景受到了广泛的关注．文章介绍了SPPs的基本性质和表面等离子体亚波长光学(surface plasmons subwavelength optics)研究中的热点问题及发展方向．     

基于后焦面成像的聚合物平面波导光学参数测量仪

基于后焦面成像确定波导传播特性的基本原理,结合平面波导中的菲涅尔反射理论,设计了一种聚合物平面波导光学参数测量仪.通过MATLAB拟合处理数据实现了对样品局部折射率和厚度高精度、高空间分辨率的实时测量,平面波导厚度测量精度可以达到纳米量级,空间分辨率可达到300 nm.该测量仪结构简单、易于操作,在光学传感和细胞内生物传感领域具有很高的应用价值.     

铌酸钾钠基无铅压电陶瓷烧结及极化工艺优化

采用传统固相法在烧结温度1 110～1 150℃内成功制备了(K_0.5Na_0.5)_0.98Li_0.02Nb_0.77Ta_0.18Sb_0.05O₃(LTS-KNN)无铅压电陶瓷,所有样品结晶性良好,无第二相产生。在1 130℃下烧结的压电陶瓷致密度良好,陶瓷表现出较好的压电性能。通过调节极化电场与极化温度可改善陶瓷的极化程度,进而优化陶瓷的压电性能。实验结果表明,在烧结温度为1 130℃,极化电场为3 kV/mm,极化温度为60℃时,陶瓷的压电性能达到最佳,即压电常数d₃₃ =310 pC/N,机电耦合系数k_p =48%。     

Super-Resolution Imaging on Microfluidic Super-Resolution Near-Field Structure

We present a new concept of the microfluidic super-resolution near-field structure (MSRENS) based on a microfluidic structure and a super-resolution near-field structure. The near-field distance control, “nano-probe” and scanning can be realized simultaneously using the MSRENS, which is similar to a near-field scanning optical microscope. The design and simulation results are presented. Numerical simulation has demonstrated that the MSRENS with spatial resolution beyond the diffraction limit could be applicable in chemistry, biologics, and many other fields.     

Fluorescence Enhancement of a Polymer Planar Waveguide Doped with Rhodamine B and Ag Nanoparticles

Planar polymer multi-model waveguides doped with Ag nano-particles and rhodamine B are fabricated and investigated by the spectroscopy analysis method as well as the M-line method. Experimental results shown that fluorescence enhancement occurs when excited by a wide band wavelength with Ag nano-particle concentration at a certain level. The maximum enhancement factor in our experiment is obtained to be about 3.8 when excited by 350 nm. Our study may have potential applications in polymers optical elements, such as polymer waveguide lasers and amplifiers.     

Temperature Effects on Prism-Based Surface Plasmon Resonance Sensor

We theoretically analyse the temperature effects on a surface plasmon resonance （SPR） sensor in Kretschmann configuration. The temperature effects include the thermo-optic effect and the dispersion of thermal-optic coefficient in the dielectric along with the thermal expansion effect, phonon-electron scattering and electron-electron scattering in the metal layer. We simulate the temperature dependence of the resonance position and the sensitivity of the SPR sensor under wavelength-interrogation and angular-interrogation mode of operation and the differences are pointed out in the two modes.