Terahertz Compression in Ultrafast Electron Microscopy for Breakthrough Time Resolution

未来频率为光（太赫兹和太赫兹）的电子器件的基石是纳米尺寸的光子器件，结合石墨烯或MXenes等超快速响应晶格。对这些材料及其动力学的深刻理解需要能够在空间和时间中看到电场、磁场和原子晶格的示波器测量技术。在这个项目中，我们计划在时间上以几飞秒分辨率和在空间上以纳米分辨率可视化光场。为此，我们将开发下一代电子显微镜：通过用单周期太赫兹场压缩激光触发的电子脉冲，我们将首次在透射电子显微镜中获得几秒的孤立电子脉冲，比以前短10到100倍。利用这种电子探针，我们将进行原理验证泵浦探针实验，以解决纳米结构中的光场和2d材料中的超快晶格变换，以便了解它们的场驱动动力学，作为未来超快设备和电路设计的基础。

The building bricks of future electronics at frequencies of light (terahertz and petahertz) are nanometer-sized photonic devices in combination with ultrafast-response lattices such as graphene or MXenes. A profound understanding of such materials and their dynamics requires oscilloscopic measurement techniques that are capable of seeing electric and magnetic fields and atomic lattices in space and time.In this project, we plan to visualize optical fields with few-femtosecond resolution in time and nanometer resolution in space. To this end, we will develop a next-generation electron microscopy: By compressing laser-triggered electron pulses with single-cycle terahertz fields, we will for the first time obtain few-fs isolated electron pulses in a transmission electron microscope, ten to hundred times shorter than before. Using the so-created electron probes, we will perform proof-of-principle pump-probe experiments to resolve light fields in nanostructures and ultrafast lattice transformations in 2D-materials, in order to understand their field-driven dynamics as a basis for the design of future ultrafast devices and circuitry.