Ultrafast nanooptics: Plasmon Coupling, Propagation, and Interference on the Nanoscale, using femtosecond photoemmission microscopy

超快纳米光学：使用飞秒光电子显微镜进行纳米尺度的等离子耦合、传播和干涉

• 批准号: 137686450
• 负责人: Professor Dr. Frank-Joachim Meyer zu Heringdorf
• 金额: --
• 依托单位: Forschungsgruppe Experimentalphysik
• 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/137686450?language=en
• 关键词: Ultrafast; nanooptics; Plasmon; Coupling; Propagation

The coupling of light into metallic structures, and the guiding, manipulation, and conversion back into light is extremely desirable, because this would revolutionize modern telecommunication and computing technology. The optical losses in metals are too large to transport light directly, however, and the light must be converted into a surface plasmon polariton (SPP), i.e., a charge-density wave that propagates at the interface between the metallic surface and the surrounding medium. In his previous work, the applicant has developed a technique to visualize SPP waves at the surface of Ag islands with two photon photoemission microscopy (2PPE PEEM). 2PPE PEEM relies on femtosecond (fs) laser pulses for illumination of the surface and provides plasmon-enhanced nonlinear photoemission images with video rate. During the first funding period, the applicant demonstrated that 2PPE PEEM can be used to study the excitation of SPPs with fs laser pulses, that SPP propagation can be observed, and that 2PPE PEEM is suitable to study the coupling of SPPs back into light. By covering the surface of an Ag island by only a few nm C60, the properties of the SPP were gradually changed. The present proposal aims at a fundamental understanding of the SPP propagation and interaction with matter. In the newly developed normal incidence (NI) geometry in 2PPE PEEM, the plasmon-related contrast provides a more detailed picture of the propagating SPP. Using NI in a pump-probe experiment, it should be possible to observe a SPP wave packet directly while it travels across the surface, is reflected, or is converted back into light. Using SPP interference and controlled phase shifts between pump and probe pulses of different polarizations, the optical near field behind the islands will be controlled with a resolution close to the diffraction limit.

将光耦合到金属结构中，并引导、操纵和转换回光是非常可取的，因为这将彻底改变现代电信和计算技术。然而，金属中的光学损耗太大而不能直接传输光，并且光必须被转换成表面等离子体激元（SPP），即，在金属表面和周围介质之间的界面上传播的电荷密度波。在他以前的工作中，申请人已经开发了一种技术，用双光子光电发射显微镜（2 PPE PEEM）在Ag岛的表面可视化SPP波。2 PPE PEEM依赖于飞秒（fs）激光脉冲照射的表面，并提供等离子体增强的非线性光电发射图像与视频速率。在第一个资助期内，申请人证明了2 PPE PEEM可用于研究用fs激光脉冲激发SPP，可以观察到SPP传播，并且2 PPE PEEM适合研究SPP返回光的耦合。通过仅用几nm的C60覆盖Ag岛的表面，SPP的性质逐渐改变。本建议旨在从根本上了解SPP传播和与物质的相互作用。在2 PPE PEEM中新开发的垂直入射（NI）几何结构中，等离子体相关的对比度提供了传播SPP的更详细的图像。在泵浦-探测实验中使用NI，当SPP波包穿过表面、被反射或转换回光时，应该可以直接观察到它。使用SPP干涉和不同偏振的泵浦和探测脉冲之间的受控相移，岛后面的光学近场将被控制为具有接近衍射极限的分辨率。