time-resolved μARPES and TOF-PEEM setup (Teilfinanzierung)

我们提出了一种“μm”尺寸的实空间视场（tr-μ arpes）和时间分辨光发射电子显微镜（tr- peem）的时间分辨和角度分辨光发射光谱装置。该装置将包括一个100kHz激光放大器，一个具有差频产生（DFG）的光学参数放大器（OPA），用于有效地产生中红外泵脉冲，一个（极）紫外探针脉冲源，一个配备飞行时间光电电子显微镜（也称为飞行时间动量显微镜）的TOF-PEEM室，一个氦冷却样品显微镜台，一个样品制备室和一个负载锁。该装置将使我们能够测量实空间和倒易空间中的非平衡载流子动力学，以及暴露于可见光、红外和强场MIR泵浦脉冲下的各种低维固体和二维异质结构的瞬态能带结构。与传统的半球形分析仪相比，设想的TOF-PEEM具有重要的优势，包括：(1)可以在实空间和互反空间中拍摄图像，在单次拍摄中可以访问整个光电发射水平；(2)可以在μARPES模式下减少TOF-PEEM的视场，这将使我们能够测量小样品或非均匀样品的能带结构。100kHz的重复频率将确保良好的信噪比，合理的集成时间和减轻空间电荷问题。低温可以让我们得到各种对称破缺的基态。该装置将用于研究扭曲范德华异质结构中的载流子动力学以及不同低维固体在准周期MIR驱动下的瞬态能带结构。

We propose a setup for time- and angle-resolved photoemission spectroscopy with "μm" -sized field of view in real space (tr-μARPES) and time-resolved photoemission electron microscopy (tr-PEEM). The setup will include a 100kHz laser amplifier, an optical parametric amplifier (OPA) with difference frequency generation (DFG) for the efficient generation of mid-infrared pump pulses, a source for the generation of (extreme) ultraviolet probe pulses, a TOF-PEEM chamber equipped with a time-of-flight photoemission electron microscope (also referred to as time-of-flight momentum microscope), a Helium-cooled sample microscopy stage, a sample preparation chamber, and a load lock. This setup will allow us to measure the non-equilibrium carrier dynamics both in real and reciprocal space and the transient band structure of various low-dimensional solids and two-dimensional heterostructures exposed to visible, infrared, as well as strong-field MIR pump pulses. The envisioned TOF-PEEM offers important advantages compared to more conventional hemispherical analyzers including (1) the possibility to take images both in real and reciprocal space where the whole photoemission horizon can be accessed in a single shot, and (2) the possibility to reduce the field of view of the TOF-PEEM in μARPES mode which will allow us to measure the band structure of small or inhomogeneous samples. The repetition rate of 100kHz will ensure excellent signal-to-noise ratios for reasonable integration times and mitigate space charge issues. Cryogenic temperature will allow us to access various symmetry-broken ground states. The setup will be used to investigate carrier dynamics in twisted van der Waals heterostructures as well as the transient band structure of different low-dimensional solids exposed to quasi-periodic MIR driving.