Periodic Reporting for period 2 - QEWS (Quantum Electron Wavepacket Spectroscopy)
Reporting period: 2023-04-01 to 2024-09-30
In this ERC project we develop a new prototype instrument for Photon-Induced Near-Field Electron Microscopy (PINEM) using a scanning electron microscope. In PINEM the interaction with high-energy electrons and intense laser fields is used to study the nanoscale spatial distribution of the light fields. Vice, versa, the electron-light interaction can be used to modify the properties of the electron itself. The project aims to create tailored light fields to create quantum-mechanical wavepackets with tailored distributions in space and time. The new prototype instrument can be used to explore novel forms of ultrafast, nanoscale optical spectroscopy that can fiend applications in photovoltaics, photonic integrated circuits, sensors, and more.
In the first half of the project, we have constructed the first version of the prototype instrument, combining a scanning electron microscope (SEM) system with light detection (cathodoluminescence, CL) and a light incoupling system that is designed for optimum coupling between the electron beam and the laser-driven optical near field to create the PINEM effect. We developed a light and electron detection and alignment system in the SEM so that the spatial and temporal overlap of laser and electron beams can be optimized. We developed a retarding-field electron energy analyzer (RFA) and integrated it in the SEM/CL chamber so that the energy gain spectrum can be measured. We have developed and tested several metamaterials geometries to optimize the coupling between electrons and light fields.
These are all breakthroughs advancing the research field significantly beyond the state of the art. The development of the new fiber/light-collection platform was completely unplanned. The expansion of the retarding field analyzer to energies above 10 keV makes it suitable for a wide range for applications in scanning electron microscopy.