Simultaneous spatial and temporal control of the local excitation of a nanostructure using polarization-shaped laser pulses

在这一资助期间，我们希望建立相干2D纳米显微镜与基于脉冲整形的相干控制相结合的新方法，以获得对纳米系统相干超快过程的洞察。具体地说，我们将研究耦合(激子和/或等离子体)系统中的光致相干以及它们在亚衍射空间和飞秒时间分辨率下的输运。为此，我们在第一个资助期展示了纳光激发的自适应和分析控制，以及电子相干的次衍射谱的一种新方法。在即将到来的资助期，我们计划进一步开发、推广并最终结合这些方法，同时也要借助更多的技术进步。然后，我们将把这些方案应用于一些纳米级系统。尤其是相干2D纳米技术有望观察到电子相干和布居的时空关联过程。通过这种方法，我们将非线性技术的原理从系综测量推广到纳米尺度，并在空间上定位了少数几个发射体。因此，我们可以绘制出时间/频率以及真实空间中的非线性响应函数。二维纳米技术可以被认为是时间分辨双光子光电发射的推广。我们想要证明，2D方法在光电子研究领域具有类似的有益价值，就像它已被证明用于光学光谱和核磁共振一样。因此，研究以其他方式无法获得的一系列引人入胜的量子现象应该成为可能。纳米结构、分子或用于光伏发电的天然和人工光捕获系统的非线性光谱学中可能有应用。与纳米光激发控制相结合，将进一步实现对输运过程的直接空间分辨研究。

In this funding period, we want to establish coherent 2D nanoscopy in combination with pulse-shaping-based coherent control as novel methods for gaining insight into coherent ultrafast processes of nanoscale systems. Specifically we will study light-induced coherences in coupled (excitonic and/or plasmonic) systems and their transport with subdiffraction spatial and fs temporal resolution. For this purpose, we have demonstrated in the first funding period the adaptive and analytic control of nanooptical excitation as well as a new method for subdiffraction spectroscopy of electronic coherences. In the upcoming funding period, we plan to further develop, generalize, and ultimately to combine these methods, also with the help of additional technological advances. We will then apply these schemes to a number of nanoscale systems. Especially the technique of coherent 2D nanoscopy holds promise to observe processes of spatial–temporal correlations of electronic coherences and populations. With that method we carry the principle of nonlinear techniques from an ensemble measurement to the nanometer length scale and spatially localized few emitters. Thus we can map out nonlinear response functions in time/frequency as well as real space. 2D nanoscopy can be considered a generalization of time-resolved two-photon photoemission. We want to show that the 2D method can be of similar beneficial value for the field of photoemission research as it has proven to be for optical spectroscopy and NMR. It should thus become possible to study a broad range of fascinating quantum phenomena not accessible otherwise. Possible applications are envisaged in the nonlinear spectroscopy of nanostructures, molecules, or natural and artificial light-harvesting systems used in photovoltaics. Combination with the nanooptical excitation control will furthermore allow the direct spatially resolved study of transport processes.