Characteristics of the Coupled-Resonator Structure Based on a Stub Resonator and a Nanodisk Resonator

A coupled-resonator structure consisting of a stub resonator and a nanodisk resonator is proposed and numeri- cally investigated by using a two-dimensional finite element method. Simulation results show that two resonant modes occur in the transmission spectra, and the sharp and asymmetric Fano-lines increase with the wavelength resolution. We also analyze the properties of two resonant modes of the structure and design a similar structure supporting only one resonant mode, which has better wavelength resolution. Our models are important for improving the wavelength resolution in plasmonic devices and the sensitivity in sensors.     

Millimeter Propagation and High Confinement in Rhombus-Based Hybrid Plasmonic Waveguides

A hybrid plasmonic waveguide, consisting of two dielectric nanowires symmetrically put at the opposite corner angles of a rhombic metM, is proposed and numerically analyzed by the finite-element method. Simulations show that the present waveguide can achieve the millimeter propagation distance （1244 μm） and deep subwavelength mode area （5.5 × 10-3 μm2）, simultaneously. Compared with the previous hybrid waveguides based on cylinder nanowires or fiat films, the rhombie corner angles enable our waveguide to achieve both longer propagation distance and smaller mode area. This is due to the enhanced coupling between the dielectric guided mode in nanowires and the surface plasmon polariton mode at rhombic surface. Furthermore, the extreme confinement near the rhombic corner angles can strengthen the light-matter interaction greatly and make the present waveguide useful in many applications, such as nonlinear photonics, high-quality nanolazers and nanophotonic waveguides.     

三元乙丙橡胶玻璃化转变温度以上的Sub-Rouse弛豫峰研究

采用动态力学分析法(DMA)研究了三元乙丙橡胶(EPDM)的链段弛豫行为.结果表明随着温度的升高,EPDM样品依次出现了3个内耗弛豫峰,分别是玻璃化转变(α转变)、sub-Rouse模式转变(α'转变)和Rouse模式转变(α″转变).通过分析频率谱中弛豫时间、弛豫强度、耦合参数和形状因子分别随温度的变化,发现在温度为384 K处,sub-Rouse模式转变存在动态转折点TB.而且,转折点的弛豫时间τα'(TB)大约是0.11 s,这与文献报道的PS及PVAc/PEO共混物(10(-0.5±0.5)s)等材料的弛豫时间非常接近,表明该转折点是在特定的弛豫时间产生的.基于链段耦合模型,我们提出此转折点是由低于TB温度时分子间耦合增强引起的.