Sie Edbert J, Rohwer Timm, Lee Changmin, Gedik Nuh
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Nat Commun. 2019 Aug 6;10(1):3535. doi: 10.1038/s41467-019-11492-3.
High harmonic generation of ultrafast laser pulses can be used to perform angle-resolved photoemission spectroscopy (ARPES) to map the electronic band structure of materials with femtosecond time resolution. However, currently it is difficult to reach high momenta with narrow energy resolution. Here, we combine a gas phase extreme ultraviolet (XUV) femtosecond light source, an XUV monochromator, and a time-of-flight electron analyzer to develop XUV-based time-resolved ARPES. Our technique can produce tunable photon energy between 24-33 eV with an unprecedented energy resolution of 30 meV and time resolution of 200 fs. This technique enables time-, energy- and momentum-resolved investigation of the nonequilibrium dynamics of electrons in materials with a full access to their first Brillouin zone. We evaluate the performance of this setup through exemplary measurements on various quantum materials, including WTe, WSe, TiSe, and BiSrCaCuO.
超快激光脉冲的高次谐波产生可用于进行角分辨光电子能谱(ARPES),以飞秒时间分辨率绘制材料的电子能带结构。然而,目前很难在窄能量分辨率下达到高动量。在此,我们结合气相极紫外(XUV)飞秒光源、XUV单色仪和飞行时间电子分析仪,开发了基于XUV的时间分辨ARPES。我们的技术可以产生24 - 33 eV之间的可调光子能量,具有前所未有的30 meV能量分辨率和200 fs时间分辨率。该技术能够对材料中电子的非平衡动力学进行时间、能量和动量分辨研究,并能完全进入其第一布里渊区。我们通过对各种量子材料(包括WTe、WSe、TiSe和BiSrCaCuO)的示例性测量来评估该装置的性能。