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

在此资助期内，我们希望建立相干二维纳米显微镜与基于脉冲形状的相干控制相结合的新方法，以深入了解纳米级系统的相干超快过程。具体来说，我们将研究耦合（激子和/或等离子体）系统中的光诱导相干及其亚衍射空间和时间分辨率的输运。为此，我们在第一个资助期展示了纳米光激发的自适应和分析控制，以及电子相干亚衍射光谱的新方法。在即将到来的融资期内，我们计划进一步发展、推广并最终结合这些方法，同时也借助其他技术进步。然后，我们将把这些方案应用于一些纳米级系统。特别是相干二维纳米技术有望观察电子相干和居群的时空相关过程。该方法将非线性技术的原理从系综测量扩展到纳米尺度和空间局域化的少量发射体。因此，我们可以在时间/频率和实空间中绘制非线性响应函数。二维纳米显微镜可以被认为是时间分辨双光子光电发射的推广。我们想要证明二维方法可以在光谱学和核磁共振研究领域具有类似的有益价值。因此，研究广泛的、令人着迷的量子现象将成为可能。可能的应用设想在纳米结构的非线性光谱，分子，或用于光伏的自然和人工光收集系统。结合纳米光学激励控制将进一步允许直接的空间分辨研究输运过程。

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.