Three-dimensional plasmonic micro projector for light manipulation.
Three-dimensional plasmonic micro projector for light manipulation.
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DOI：
10.1002/adma.201203308
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发表时间：
2013-02-25
影响因子：
29.4
通讯作者：
Tsai, Din Ping
中科院分区：
文献类型：
--
作者：
Chang, Chia Min;Tseng, Ming Lun;Cheng, Bo Han;Chu, Cheng Hung;Ho, You Zhe;Huang, Hsin Wei;Lan, Yung-Chiang;Huang, Ding-Wei;Liu, Ai Qun;Tsai, Din Ping
表面等离子体激元[1]（SPP）的应用在光电子学领域得到了广泛的发展，例如等离子体电路（例如波导、干涉逻辑和调制器）[2]、纳米激光器[3]、超高效率传感器[4]、光电子学[5]、超分辨率成像[6]和各种二维等离子体透镜。[7]此外，利用奈米结构将SPP平面波投射到邻近的自由空间也是一个重要的课题。等离子体纳米结构与SPP波的相互作用不仅涉及面内行为，还涉及面外散射，面外散射被捕获为远场辐射光。[8]人们提出了几种将受限表面等离子体激元转换为辐射波的理论方法。[9]非常期望将等离子体激元器件的应用范围扩展到三维光操纵领域。[10]最近，由金（Au）纳米凸点组成的四分之一圆形结构对SPP波的三维聚焦和发散进行了研究。[11]分别在Au表面上方和下方观察到单个Au纳米凸点的前向和后向散射。因此，Au纳米凸块赋予SPP波额外的三维传播波矢量（k x，k y，k z）以离开表面。因此，可以通过布置Au纳米凸块来将三维等离子体散射操纵成特定几何形状，这在图1a中示意性地描绘。在本文中，我们操纵的SPP波的散射由各种等离子体结构组成的纳米凸点排列在金薄膜。在控制等离子体结构的几何形状时，可以根据需要修改散射光的高度、位置和图案。在本实验中，我们利用飞秒激光直写技术在玻璃衬底上的30 nm厚的Au薄膜上制作纳米凸点，如图1 B所示。飞秒激光直写技术作为一种无掩模制备技术，是制备各种等离子体纳米结构的一种高效、有效的方法。[3b与其他无掩模光刻技术（如电子束和聚焦离子束光刻）相比，飞秒激光直写技术的加工速度快得多，并且对实验装置的要求简单、成本低。它可用于在任意基底上制造结构，如柔性片材[13]和光纤。[14]此外，通过将聚焦激光束的能量剂量精确地设置在薄膜的烧蚀阈值以下，可以原位形成纳米凸块。[15]纳米凸块（平均高度H= 30 nm，基底直径D= 420 nm，参见图1 B中的插图）是这项工作的核心。图1 c显示了从SPP波到辐射光转换的示意图。利用全内反射显微镜（TIRM），在全内反射条件下（入射角为48 °），用横磁（TM）偏振激光束（λ= 532 nm）发射SPP波。辐射光是SPP波与纳米凸块相互作用的散射。图2a示出了从z= 730 nm获得的TIRM图像。SPP波的散射光源自单个Au纳米凸点。[11]条纹间距为504nm。为了阐明平面外散射行为，使用时域有限差分（FDTD）模拟（参见模拟方法小节）。图2 B显示了.
Applications of surface plasmon polaritons [1](SPP) have been extensively developed in the field of optoelectronics, such as plasmonic circuitry (eg, waveguides, interferometric logic, and modulators),[2] nanolasers,[3] ultrahigh-efficiency sensors,[4] photovoltaics,[5] super-resolution imaging,[6] and various twodimensional plasmonic lens.[7] Besides, using nanostructures to project SPP plane waves into the adjacent free space is also an important issue. The interactions of plasmonic nanostructure on SPP wave involve not only the in-plane behavior, but also out-of-plane scattering which is captured as the far-field radiated light.[8] A few theoretical approaches to convert the confined surface plasmons into radiated waves have been proposed.[9] It is highly desirable to extend the application range of plasmonic devices into the domain of three-dimensional light manipulation.[10] Recently, three-dimensional focusing and diverging of SPP waves by a quarter circular structure composed of gold (Au) nanobumps were studied.[11] The forward and backward scattering from individual Au nanobump are observed above and below Au surface, respectively. Hence, the Au nanobumps confer additional three-dimensional propagating wave vectors (k x, k y, k z) on SPP wave for departing from surface. Therefore, it is possible to manipulate the three-dimensional plasmonic scattering into specific geometry by arranging the Au nanobumps, which is schematically depicted in Figure 1a. In this paper, we manipulate the scattering of SPP waves by various plasmonic structures composed of arranged nanobumps on a gold thin film. Upon controlling the geometry of the plasmonic structures, the height, position, and pattern of scattered light can be modified as desired. It provides a simple and efficient way to project a specific light pattern into free space, and demonstrate the capability of three-dimensional light manipulation.In this experiment, the nanobumps are fabricated on the 30-nm-thick Au thin film on the glass substrate using the femtosecond-laser (fs-laser) direct-writing technique, as depicted in the schematic diagram Figure 1 b. Femtosecond-laser directwriting technique as a kind of maskless fabrication technique is a high-efficiency and powerful method for producing various plasmonic nanostructures.[3b, 12] In comparison with other maskless fabrication techniques (eg, e-beam and focus-ion beam lithographic methods), the processing rate of fs-laser directwriting technique can be much faster, and the requirements of experimental setup are simple and low-cost. It can be utilized to fabricate structures on arbitrary substrates such as flexible sheets [13] and optical fibers.[14] Moreover, with exactly setting the energy dose of the focused laser beam below the ablation threshold of the thin films, the nanobumps can be formed in situ.[15] The nanobump (the average height H= 30 nm and diameter of base D= 420 nm, see the inset in Figure 1 b) is the core in this work. Figure 1 c shows the schematic illustration of conversion from SPP wave to radiated light. By total internal reflection microscopy (TIRM), SPP wave is launched by the transverse-magnetic (TM) polarized laser beam (λ= 532 nm) under total internal reflection condition (incident angle of 48). The radiation light is the scattering of SPP wave interacted with a nanobump. Figure 2a shows the TIRM image which is obtained from z= 730 nm. The scattering light of SPP wave originates from an individual Au nanobump.[11] The separation of fringes is 504 nm. To clarify the out-of-plane scattering behavior, the finite difference time domain (FDTD) simulation is used (see simulation method subsection). Figure 2 b shows the …
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影响因子：
3.7
作者：
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通讯作者：
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影响因子：
29.4
作者：
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通讯作者：
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影响因子：
3.8
作者：
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通讯作者：
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