Periodic Reporting for period 1 - ANACONDA (Attosecond nanoscopy of electron dynamics instrongly correlated materials)
Reporting period: 2022-07-01 to 2024-12-31
Strongly correlated materials, like transition-metal oxides, exhibit complex behaviors due to intense electron interactions. Understanding their phase transitions between insulating and metallic states is challenging but vital for advancing electronics. This project aims to investigate these transitions using innovative, tabletop ultrafast imaging techniques. By observing dynamics from attosecond to picosecond timescales and resolving structures at the nanometer level, we seek to uncover the mechanisms and speed limits of these phase changes. The objective is to achieve precise control over these transitions, paving the way for ultra-fast electronic devices operating at petahertz frequencies and enabling technologies like resistive random-access memory (ReRAM) to reach mass production.
We developed time-resolved high-harmonic spectroscopy techniques to probe ultrafast electronic dynamics directly within solids, rather than only relying on high harmonics generated in gases. This choice provided superior signal quality and allowed for more precise measurements. We studied materials such as methylammonium lead bromide thin films as more generic example of complex (but uncorrelated) electron dynamics, which represent materials that are themselves important for perovskite solar cells, to observe how charge carriers behave under light excitation.
A significant achievement was the creation of Harmonic Deactivation Microscopy (HADES). This technique breaks the diffraction limit of optical microscopy without needing fluorescent labels, enabling imaging of non-fluorescent materials at nanometer resolutions and possibly on attosecond timescales. This advancement opens new possibilities for observing ultrafast processes in various materials.
We also investigated ultrafast phase transitions in materials like niobium dioxide, capturing the switch from insulating to metallic states within 100 femtoseconds. Additionally, we developed advanced laser systems capable of delivering powerful, ultra-short light pulses, essential for driving and studying these rapid processes.
A significant achievement was the creation of Harmonic Deactivation Microscopy (HADES). This technique breaks the diffraction limit of optical microscopy without needing fluorescent labels, enabling imaging of non-fluorescent materials at nanometer resolutions and possibly on attosecond timescales. This advancement opens new possibilities for observing ultrafast processes in various materials.
We also investigated ultrafast phase transitions in materials like niobium dioxide, capturing the switch from insulating to metallic states within 100 femtoseconds. Additionally, we developed advanced laser systems capable of delivering powerful, ultra-short light pulses, essential for driving and studying these rapid processes.
Our work pushes the boundaries of ultrafast optics and materials science by enabling imaging and control of phase transitions at unprecedented temporal and spatial resolutions. Harmonic Deactivation Microscopy (HADES) allows for the observation of non-fluorescent materials at resolutions previously achievable only with fluorescent super resolution techniques, but without their limitations. Directly observing ultrafast phase transitions within solids provides deeper understanding essential for developing ultra-fast electronics. The advanced laser systems and methods we developed enhance our ability to manipulate materials at extreme speeds and scales, potentially revolutionizing data storage technologies and electronic devices. To this end, we have also developed one of the most powerful femtosecond optical parametric chirped pulse amplifier systems operating in the midinfrared which can be used to drive soft-X-ray high-harmonic generation.