Real-time investigation of surface plasmon plariton propagation in nanoscale plasmonic phase structures

纳米级等离子体相结构中表面等离子体激元传播的实时研究

• 批准号: 138733244
• 负责人: Professor Dr. Martin Aeschlimann
• 金额: --
• 依托单位: Institut für Oberflächen- und Schichtanalytik GmbH (IFOS)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/138733244?language=en
• 关键词: Real; time; investigation; surface; plasmon

The main goal of this project is the real-time investigation of a) the fundamental interaction mechanism of propagating surface plasmon polaritons (SPP) with phase manipulative materials and b) its associated radiative and non-radiative losses observed with sub-wavelength resolution. Despite the recent significant steps in the development of functional nanoplasmonic devices, their widespread implementation still limps because of inherent losses. Several methods for loss compensation were proposed, but a detailed understanding of the microscopic origin of damping caused by the fundamental interaction processes of plasmon waves and material is still lacking. The directive SPP transport has been realized only by volumetric structuring with electron beam lithography, ion beam etch processes, self-assembled nanomasking or a complex combination of such methods. These structures are intended to solely control the lateral distribution of the SPP amplitude without a direct influence on the SPP phase. For this additional purpose we introduce the new concept of topography-free plasmonic phase structures (PPS), adding the spatial index variation as new control parameter and simultaneously avoiding scattering losses at asperities. As a result, a higher degree of freedom in the design of future plasmonic structures is gained. Plasmonic phase structures are generated by local nanoscale ion implantation of gallium into thin homogeneous layers of mono/polycrystalline gold films with a focused ion beam apparatus. In analogy to the variation of the refractive index in pure dielectric waveguides, the spatial variation of the dielectric function, controlled by the ion implantation dose / depth, allows to taylor the propagation behaviour of SPPs. This way might open the route for PPS with the perspective of a more effective and sophisticated control of SPPs. In order to engineer the optimal SPP manipulation design, a thorough characterization of the dynamical electronic as well as optical properties has to be performed on the nanoscale. The electronic properties of the material and their modification under ion implantation will be probed with time- and energy-resolved photoelectron spectromicroscopy (PEEM). The obtained time- and lateral-resolved photoelectron spectra are used to distinguish between different excitation mechanisms of non-radiative channels. The optical properties, on the other hand, will be investigated by time-resolved near-field microscopy (SNOM). To solve the inherent problem of extremely low transmission of metallic aperture probes, we are going to implement the new white light nanoscope. A dielectric sphere at the tip apex of a cantilever acts as a Mie scatterer and is supposed to show an extremely high transmission with a broad bandwidth. This paves the way to achieve femtosecond time resolution together with a 50 nm spatial resolution, that will make the local characterization of the dynamical optical properties of the new material possible.

该项目的主要目标是实时研究a)传播的表面等离子体激元(SPP)与位相可控材料的基本相互作用机制，以及b)在亚波长分辨率下观测到的辐射和非辐射损失。尽管最近在开发功能纳米等离子体器件方面迈出了重要的一步，但由于固有的损失，它们的广泛实施仍然步履蹒跚。人们提出了几种补偿损耗的方法，但对等离子体波与材料的基本相互作用过程所引起的损耗的微观来源仍缺乏详细的了解。定向SPP的传输只能通过电子束光刻、离子束刻蚀工艺、自组装纳米掩膜或这些方法的复杂组合的体积结构来实现。这些结构旨在仅控制SPP幅度的横向分布，而不直接影响SPP相位。为此，我们引入了无地形等离子体相结构(PPS)的新概念，增加了空间折射率变化作为新的控制参数，同时避免了在凹凸处的散射损失。因此，在未来的等离子体结构设计中获得了更高的自由度。利用聚焦离子束装置，在单晶/多晶金薄膜的均匀薄层中局部纳米级离子注入产生等离子体相结构。与纯介质波导中折射率的变化类似，由离子注入剂量/深度控制的介电函数的空间变化允许泰勒(Taylor)研究表面等离子体激元的传输行为。这种方式可能会从更有效和更复杂的控制战略伙伴关系的角度为伙伴关系开辟道路。为了设计最优的SPP操纵设计，必须在纳米尺度上对SPP的动态电子性质和光学性质进行彻底的表征。用时间分辨和能量分辨光电子显微镜(PEEM)研究了材料的电学性质及其在离子注入下的改性。得到的时间分辨光电子能谱和横向分辨光电子能谱用于区分非辐射通道的不同激发机制。另一方面，光学性质将通过时间分辨近场显微镜(SNOM)进行研究。为了解决金属孔径探头透过率极低的固有问题，我们将实现新的白光纳米显微镜。悬臂梁顶端的介质球起到Mie散射体的作用，应该具有极高的透射率和较宽的带宽。这为实现飞秒时间分辨率和50 nm空间分辨率铺平了道路，这将使新材料的动态光学性质的局部表征成为可能。