Optical spatio-temporal optical control of electron-induced processes at graphene-supported metal cluster nano-structures

石墨烯支撑金属簇纳米结构电子诱导过程的光学时空光学控制

• 批准号: 138792705
• 负责人: Professor Dr. Thorsten M. Bernhardt
• 金额: --
• 依托单位: Institut für Oberflächenchemie und Katalyse
• 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 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/138792705?language=en
• 关键词: Optical; spatio; temporal; optical; control

In this proposal we wish to explore the potential of optimal control with shaped ultrafast laser pulses to localize the electromagnetic field in metal nano-cluster arrays consisting of graphene-supported size-selected silver clusters with extensions from a few atoms to the nanometer scale. Nothing is known so far about the optical properties of such arrays and we expect to find interesting new phenomena in particular also because of the intriguing electronic propensities of the 2D-material graphene. Graphene is employed as a substrate to provide a geometric template, i.e., to define the cluster distances – its potential to also provide electronic coupling between the clusters will be a subject of investigation. Size-selected clusters will be employed to obtain perfectly monodisperse samples and to investigate the effect of the transition from discrete to plasmonic electronic cluster structure on the possibility of field localization. Optical excitation will be provided by modulated (frequency, phase, polarization) ultrafast laser pulses. In a new experimental approach, the effect of the electromagnetic field localization will be probed by detecting the effectiveness of the electron-emission-induced dissociation of physisorbed adsorbate molecules (CH3Br, CH3Cl) on the metal clusters. Thus, the molecular fragment (CH3) mass signal will be employed as feedback signal in the control loop to obtain the optimal electromagnetic field. The investigation of the field localization will be performed by scanning tunnelling microscopic detection of the spatial extent of the metal cluster halogenation as a function of the parameters cluster size and cluster separation.

在这个提议中，我们希望探索最优控制的潜力，用形状超快激光脉冲来定位金属纳米团簇阵列中的电磁场，这些金属纳米团簇由石墨烯支持的尺寸选择的银团簇组成，从几个原子扩展到纳米尺度。到目前为止，我们对这种阵列的光学特性一无所知，我们希望找到有趣的新现象，特别是因为二维材料石墨烯的有趣电子倾向。石墨烯被用作衬底来提供几何模板，即定义簇之间的距离——它在簇之间提供电子耦合的潜力将是一个研究课题。大小选择的团簇将用于获得完美的单分散样品，并研究从离散到等离子体电子团簇结构转变对场局域化可能性的影响。光激发将由调制的（频率、相位、偏振）超快激光脉冲提供。在一种新的实验方法中，将通过检测物理吸附的吸附分子（CH3Br, CH3Cl）在金属团簇上的电子发射诱导解离的有效性来探测电磁场定位的影响。因此，将分子片段（CH3）质量信号作为控制回路中的反馈信号，以获得最优电磁场。本文将通过扫描隧道显微镜检测金属簇卤化的空间范围作为簇大小和簇间距参数的函数来进行场定位的研究。