Dynamical control of directional nonlinear scattering from metallic nanoantennas by three-dimensional focal polarization orientation

We demonstrate that the directionality of far-field second harmonic(SH) emission generated from individual gold nanosphere can be flexibly engineered by manipulating three-dimensional(3D) focal polarization orientation of the excitation field, which is explained by the coherent interference between SH dipolar and quadrupolar emission modes. The SH dipolar emission mode is independent of the polarization direction of the fundamental field whereas the evolution of the focal polarization orientation can dramatically modify the quadrupolar emission pattern. Therefore, the resultant SH emission pattern has a polarization-dependent behavior and side scattering almost perpendicular to the propagation direction of the incident light can be observed under a specific condition. Our findings provide a novel degree of freedom for all-optical control of directional nonlinear scattering from single nanoantenna, thereby opening new possibilities for future potential applications.     

基于规范化谱主成份分析的微操作深度信息提取

针对微操作工具在测试窗口内（X-Y平面）大范围移动时，采集到的模糊图像差异较大的问题，提出了一种新的不变量特征提取方法――规范化谱图像，将其应用于深度估计可提高系统的鲁棒性。同时，利用主成份分析方法可降低数据的维数并抑制噪声的影响，使得系统的实时性和精度得到较大改善。实验结果验证了上述方法的有效性。     

Electromagnetically induced transparency in terahertz metamaterial based on two-bright-mode resonator

An electromagnetically induced transparency (EIT) in metamaterial resonator with two bright modes and one dark mode at the terahertz (THz) band is numerically and experimentally demonstrated. Different from two kinds of the traditional passive modulations, our design can realize the passive modulation of EIT phenomenon by adding another bright mode resonator. Simulated and experimental results show that the transmission peak varies for incident THz waves with different polarization directions due to its asymmetric structure, which provides a novel way to realize high efficiency switch and modulation.     

阳极电泳漆用阴离子丙烯酸树脂的合成与应用研究

合成了用于阳极电泳漆的阴离子丙烯酸树脂,研究了影响树脂电沉积效果和涂膜性能的因素,探讨了涂膜在高温和低温固化的实现途径.     

阴极电泳涂料用阳离子丙烯酸树脂的合成与应用研究

通过溶液自由基聚合合成了用于阴极电泳涂料的阳离子丙烯酸树脂,研究了影响树脂水溶性、电沉积效果和涂膜性能的因素,并详细阐述了在应用方面的研究。     

太赫兹液晶可调谐功能器件

介绍了不同液晶材料在太赫兹(THz)波段的光学各向异性和外场调制特性。在此基础上,综述了几种基于液晶与人工电磁微结构相结合的THz功能器件,该器件可实现对THz波的调谐滤波、电磁诱导透明、相位调制以及偏振控制功能等;系统地分析了液晶与人工电磁微结构的相互作用机理、THz波长尺度下液晶的外场调控规律与表面相互作用。此外,还对THz液晶光子器件的研究发展趋势进行了展望。     

Investigation on refractive index sensing of single silver nanoparticle at tightly focused light illumination

Based on the generalized Mie theory, refractive index sensing characteristics of single silver nanoparticle respectively illuminated by tightly focused linearly-polarized and radially-polarized light beams are investigated. The spectra for localized surface plasmon resonances (LSPR) under different dielectric environments demonstrate that distinct dipolar and quadrupolar resonances can be always observed for the case of radial polarization, while there is only strong dipolar resonance for the case of linear polarization. The dipolar mode has a higher sensitivity. However, the figure of merit (FOM) for the quadrupolar resonance is much higher than that for the dipolar resonance, because the quadrupolar resonance has a narrower width.     

基于双层金属光栅的高消光比高透过率太赫兹偏振器

本文设计了一种基于双层金属亚波长光栅的太赫兹偏振器,其可以实现高透过率和良好消光比的特性.该偏振器是通过微加工技术在薄石英衬底的上下表面上制备而成的.实验和模拟结果均表明,双层金属光栅具有与单层金属光栅相近的透过率、更高的偏振度和更高的消光比.在0.3～2.0 THz的频率范围内,测量的透过率在83.4%到62.7%之间,偏振度大于99.7%,消光比大于29 dB.此外,设计的两种双层金属光栅偏振器件成功地应用于太赫兹时域光谱（TeraHertz Time Domain Spectroscopy,THz-TDS）系统中,获得了超过96.2%的偏振度和超过17.1 dB的消光比.通过调整金属亚波长光栅的参数（例如间距、线宽和金属膜厚度）,可以进一步提高透过率、偏振度和消光比等特性.     

Second harmonic generation of centrosymmetric nanospheres excited by tightly-focused doughnut beams

Using the vector diffraction theory and the phenomenological model, this paper investigates the second harmonic generation (SHG) of a single centrosymmetric nanosphere excited by focused doughnut beams (DBs) with different topological charges. The results show that strong backward SHG (BSHG) appears when the particle is excited by focused DBs with topological charges of . The backward second harmonic radiation can be caused by the depolarized effect of high numerical aperture (NA) objectives due to the strong longitudinal components.     

高亮度LED铁路信号机光学系统研究

研制了一种新型LED阵列和相匹配的聚光透镜阵列构成的高亮度LED铁路信号机光学系统。进行了光学结构设计和理论计算,作了实验测试。测试结果表明,红、黄、绿、蓝和自信号机沿光轴中心光强分别大于2100、3900、2800、400和3200cd,均达到铁路信号机各项光学指标,可代替传统的以白炽灯为光源及有色玻璃螺纹聚光镜构成的铁路信号机光学系统,具有亮度高、节能和寿命长等优点。