Imaging spin polarimeter for momentum microscopy

我们要求一个成像自旋偏振仪，将增加自旋分辨率到现有的设置能量，时间和动量分辨的光电子显微镜与fs-XUV辐射。这种升级的设置是Cinchetti集团计划和正在进行的研究活动的核心，其最终目标是在尽可能短的长度和时间尺度上理解和光学操纵固体中的磁性和电子特性。该提案是两个已经批准的主要仪器提案的后续行动，这两个提案分别是采购飞秒极紫外（fs-XUV）源和飞行时间动量显微镜系统。后一种仪器将升级与这里要求的成像自旋偏振仪，以实现一个先进的设置自旋角和时间分辨光电子能谱显微镜。这种结合将使我们能够执行尖端的光电发射实验，这些实验计划在我们小组正在进行的以及未来的研究活动中进行。正在进行的活动包括ERC合并项目hyControl以及FET开放项目SINFONIA和INTERFAST，计划在这些项目中进行自旋分辨飞秒分子轨道测绘实验。此外，在DFG TRR 160的项目B 9中，我们将以飞秒时间分辨率在整个布里渊区绘制磁有序2D材料的自旋极化能带结构的时间演化。最后，在“MERCUR合作”项目中，我们计划与Saraceno教授（RUB波鸿）一起建立一个超快光谱工具，该工具基于最先进的超快激光技术，具有独特的性能和灵活性，专为分子系统的自旋分辨光电子能谱而量身定制。这些正在进行的项目，以及我们小组未来的研究活动（包括TRR 160第三阶段计划的三个项目），对整个设置和成像旋光仪提出了一系列苛刻的要求。特别是，该仪器必须允许无缝集成在现有的动量显微镜系统，并使按需切换到自旋分辨操作模式。此外，该设备应允许并行检测自旋过滤动量分辨光电发射强度。由于追求我们的科学目标需要高分辨率的自旋分辨动量映射，偏振计必须采用具有低马赛克扩展的散射目标表面，并呈现出与传统的自旋极化低能电子衍射偏振计的最先进性能相媲美的单像素品质因数。最后，由于时间分辨的光电发射瞬态的强度通常很小，偏振计必须确保长时间的不间断数据采集，并依赖于在超高真空条件下具有长寿命的散射目标。

We request an imaging spin polarimeter that will add spin resolution to an existing setup for energy-, time- and momentum-resolved photoemission-microscopy with fs-XUV radiation. This upgraded setup is at the core of most of the planned and ongoing research activities of the Cinchetti group, whose ultimate goal is the understanding and the optical manipulation of magnetic and electronic properties in solids on the shortest possible length- and time-scales. This proposal is the follow-up of two, already approved, major instrumentation proposals for the procurement of a femtosecond extreme ultraviolet (fs-XUV) source and of a time-of-flight momentum microscope system. The latter instrument will be upgraded with the here requested imaging spin polarimeter to realize an advanced setup for spin- angle- and time-resolved photoemission spectro-microscopy. This combination will allow us to perform the cutting-edge photoemission experiments that are planned in the ongoing as well as future research activities of our group. The ongoing activities include the ERC consolidator project hyControl as well as the FET-OPEN projects SINFONIA and INTERFAST, where it is planned to perform spin-resolved femtosecond molecular orbital mapping experiments. In addition, in project B9 of the DFG TRR 160, we will map the time evolution of the spin-polarized band structure of magnetically ordered 2D materials, throughout the whole Brillouin zone, with femtosecond time resolution. Finally, in a "MERCUR Kooperation" project we plan, together with Prof. Saraceno (RUB Bochum), to build an ultrafast spectroscopic tool with unique performance and flexibility based on state-of-the-art ultrafast laser technology specifically tailored for spin-resolved photoemission spectroscopy of molecular systems. Such ongoing projects, as well as the future research activities of our group (that include three projects planned for the third phase of the TRR160), pose a set of demanding requirements on the whole setup and on the imaging spin polarimeter. In particular, the instrument must allow for a seamless integration in the available momentum microscope system and enable on-demand switching to the spin-resolved mode of operation. Moreover, the device should allow in-parallel detection of the spin-filtered momentum-resolved photoemission intensity. As high-resolution spin-resolved momentum mapping is required to pursue our scientific goals, the polarimeter must employ a scattering target surface with low mosaic-spread and present a single-pixel figure of merit comparable with the state-of-the-art performance of conventional spin-polarized low-energy-electron-diffraction polarimeters. Finally, due to the generally small intensity of the time-resolved photoemission transients, the polarimeter must ensure prolonged periods of uninterrupted data acquisition, and rely on a scattering target with proven long-lifetime in ultra-high-vacuum conditions.