Room-Temperature Fluorescence Lifetime of Pseudoisocyanine (PIC) J Excitons with Various Aggregate Morphologies in Relation to Microcavity Polariton Formation

The results of room-temperature fluorescence lifetime measurements are reported for the excitation of J aggregates (Js) of pseudoisocyanine chloride (PIC-Cl) prepared in potassium polyvinyl sulfate (PVS) polymer thin films, their aqueous solutions, and NaCl aqueous solutions. Variations of the microscopic morphologies of the aggregates were investigated. The results show that fluorescence decay features correlated to the morphology change. The observed fluorescence lifetime and quantum efficiency of PIC J aggregates (PIC-Js) in a NaCl aqueous solution were 310 ps and 28%, respectively. The lifetime of the fibril-shaped macroaggregates prepared in PVS thin films was below the instrumental time resolution of 5 ps, and the efficiency decreased to below 3%. The results indicate that PIC-Js prepared with PVS polymers have an increased nonradiative contribution to the excitation deactivation process. In particular, macro-Js with isolated fibril-shaped structures revealed nonradiative pathway(s) that are closely associated to the specific packaging morphology of the constituent meso-Js. The possibility of a destructive effect on the formation of cavity-polaritons is also discussed.     

表面等离子体透射增强提高光刻分辨率的模拟

讨论了表面等离子体透射增强现象在提高分辨率上的应用,数值模拟结果显示采用这种方法光刻的分辨率可以达到32nm。首先用FDTD法模拟了一维周期光栅结构的电场场强的分布,光栅模版具有三角形的脊,整个模版覆盖了一层Ag,然后讨论了三角形底角角度变化对透射率和分辨率的影响。当角度在57°～64°之间变化时,得出三角形脊部有透射增强现象产生,最大透射振幅是入射光的4.2倍,分辨率为(30±5)nm。因为凹槽部分透射光强度很小,因此具有很好的分辨率。通过对比周期和非周期边界条件模拟,三角形脊的形状是产生透射增强现象的原因。     

Effect of dipole location on profile properties of symmetric surface plasmon polariton mode in Au/Al2O3/Au waveguide

This study uses a dipole embedded in Al2O3 layer to excite a symmetric surface plasmon polariton (SPP) mode in Au/Al2O3/Au waveguide to investigate its profile properties by using finite-difference tim...     

A broadband analysis of the optical properties of silver nanoparticle films by in situ real time spectroscopic ellipsometry

A broadband analysis of the optical properties of silver nanoparticle films over the range from 0.75 to 6.5 eV was performed by applying in situ real-time spectroscopic ellipsometry (RTSE) during the nucleation, coalescence, and bulk thin film growth regimes. The dielectric functions of the particulate films were found to depend strongly on the particle size and film thickness from the nucleation regime throughout coalescence. These dependences were analyzed by separately characterizing the three types of transitions evident in the dielectric function: intraband, particle plasmon polariton, and interband. Throughout the film growth regimes, the thickness evolution of the amplitude, energy, and broadening parameter for each type of transition is discussed in view of the structural characteristics of the films, as corroborated ex situ by atomic force microscopy for films deposited over different time durations.     

非周期三角光栅表面等离子体激元透镜研究

提出了一种新的表面等离子体激元透镜结构,该结构通过在两个亚波长小孔的外表面放置非周期的三角形电介质光栅实现对入射光束的有效汇聚。利用时域有限差分法(FDTD)计算了该结构中的稳态电磁场分布,讨论了光栅数目对成像特性的影响,计算发现,聚焦光斑可能出现一个、二个甚至三个;探讨了光栅折射率对成像的影响,发现在一定介质范围内,随着折射率的增大,焦距也随之增大;除此之外,亚波长小孔的数目、光栅中心距离小孔的位置及中间无三角形等因素都在不同程度上对透镜的成像特性有一定影响。     

Plasmonic micro-optical components utilizing nanoparticle arrays: Theoretical approach

The operation of a micro-optical components for surface plasmon polaritons (SPPs) formed by nanoparticle structures is modeled in the framework of a vectorial dipolar approach for multiple SPP scattering. It is shown that the nanoparticle structures can be used for efficient splitting, directing, and focusing of SPPs. The article is published in the original.     

一种金属亚波长缝槽结构的高方向性辐射研究

本文设计了一种基于银-铝-银复合膜层结构的金属亚波长缝-槽结构。该结构由亚波长狭缝和周期性沟槽组成，在632.8 nm波长下，可实现远场的高方向性辐射。文中用有限元法分析了狭缝宽度、沟槽深度和沟槽周期对出射光高方向辐射特性的影响，并据此优化得到了器件的结构参数。使用搭建的光学远场测试平台对该缝-槽结构进行测试发现，结构的远场发散角约为4.1°，测量结果与仿真结果基本吻合，进一步证实结构的远场高方向性辐射特性。     

黄昆方程及应用

黄昆方程是黄昆先生在１９５１年提出的。这里黄昆先生首次提出了光子与横光学声子相互耦合形成新的元激发──极化激元，后来为实验所证实。目前，国际上公认黄昆先生是声子极化激元概念的首先提出者。当前，国际上关于固体中光散射的研究比较活跃，激光的固体拉曼散射谱能够提供晶体中极化激元的详细信息。这是当前固体物理和激光物理两个领域中引人注目的新动向。