基于等离激元纳腔的单颗粒稀土掺杂纳米晶上转换发光光谱调控

等离激元纳腔可有效调控稀土掺杂纳米晶的上转换发光特性,其不仅能增强上转换发光强度,还可实现上转换发光光谱的调节.然而,目前利用纳腔进行上转化发光光谱调节的研究主要基于系综实验.相比系综实验,单颗粒实验由于可对同一颗上转换纳米晶进行对比研究,因而能够排除系综样品非均匀性对实验的影响.本文基于原子力显微镜原位纳米操纵技术将...     

A Method Based on FBM Self similar Image Model for Digital Hologram SynthesisSupported by National Natural Science Foundation of China.

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无透镜傅里叶变换全息图在欠采样条件下的数值再现分析

在理论分析无透镜傅里叶变换全息图记录的基础上,结合CCD的结构特点,用傅里叶频谱方法具体研究了无透镜傅里叶变换全息图在欠采样条件下的再现问题.指出在无透镜傅里叶变换全息术中,对有限尺寸物体而言,在记录过程不满足申农（Shannon）采样定理的条件下,仍能完整再现出物体的像.同时对再现像的变化特点进行了理论说明.所得的实验结果与理论分析一致.     

新型等离子光催化剂纳米金-钛酸锌复合物的制备与光解水制氢性能

利用溶胶-凝胶法及光沉积法制备纳米金-钛酸锌(Nano Au-ZnTiO₃)复合等离子光催化剂。 采用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、紫外可见漫反射光谱、荧光光谱、光电流密度、光催化制氢性能等技术手段和测试表征了样品的结构及性能。 结果表明,ZnTiO₃在900 ℃煅烧下呈立方相和六角相的混合相,其形貌呈近似球形,粒径约为50~100 nm。 由于纳米金(Nano Au)的表面等离子共振效应,Nano Au-ZnTiO₃复合材料在可见光区有较强的吸收,吸收峰位于525 nm处。 Nano Au-ZnTiO₃复合等离子光催化剂在可见光激发下呈现出优良的光催化分解水制氢活性。     

New combined polymer/chromium approach for investigating the phototransformations involved in hologram formation in dichromated poly(vinyl alcohol)

The photochemical behavior of dichromated poly(vinyl alcohol) films has been analyzed upon exposure at 365 nm in relationship with the performances of holograms recorded in such photosensitive materials. The evolution of both involved species, poly(vinyl alcohol) and chromium, has been quantified by the implementation of an innovative approach. This approach combines the monitoring of the structural modification of the polymeric matrix and the fate of the various chromium species. For the first time, it has been established that chromium(V) not only is an indicator of the hologram quality, as previously assessed, but also appears to be responsible for the crosslinking implied in the hologram formation. Actually, the crosslinking has been proved to proceed through coordination bonds around chromium(V), which acts as a bridge between the polymeric chains. The role played by the ammonium cations in the hologram quality has also been elucidated. The improvement brought by ammonium dichromate with respect to potassium dichromate involves amide groups resulting from poly(vinyl alcohol) phototransformation. These groups provide additional chelating sites for chromium(V), leading to an increase in the matrix crosslinking. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1317–1325, 2006     

无衍射光束的特性和生成方法

介绍了无衍射光束的概念和传输性质，描述了应用常规的光学元件和计算机产生的全息图生成无衍射光束的方法及其潜在的应用价值。     

Interferometric moiré pattern encoded security holograms with concealed phase object

This paper describes an interferometry-based scheme for concealing phase objects in a security hologram. The decoding process is based on geometrical moiré technique and requires a key for hologram authenticity verification. Decoding process is straightforward and could be carried out in white light, making it suitable for validation of security holograms. The method is described and experimental results are presented.     

纳米金属肋混合表面等离子体波导模式特性分析

基于传统混合表面等离子体波导,提出了一种半导体纳米线和纳米金属肋混合的表面等离子体波导.采用有限元法对其模式特性进行了数值模拟,研究了该波导的有效折射率、传播损耗、归一化模场面积等特性随波导几何尺寸的变化规律,分析了该混合波导的增益阈值.结果表明:该波导具有较低的传播损耗和较强的光场限制能力,并且混合模式的最小模面积仅为0.001 52μm2.     

Plasmon‐enhanced Raman scattering by suspended carbon nanotubes

We report plasmon‐enhanced Raman scattering of the order of 10³ by a metallic carbon nanotube partially suspended inside a near‐field cavity. The tube is part of a small bundle, and is interfaced with an Au nanodisc dimer using a recently developed assembly scheme based on dielectrophoretic deposition. Spatially resolved Raman measurements with two excitation wavelengths and two orthogonal polarizations confirm that the enhancement arises from a 65 nm long suspended tube segment. We show that the orientation of the tube inside the cavity can be as effective for generating enhancement as placing the nanotube precisely in a plasmonic hotspot. Position and shape of the G‐peak show that the suspended part of the tube is free of strain and doped with a Fermi energy shift ≤40 meV. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)