【时  间】2025年3月4日（周二）下午2点

【地  点】Room 526

【主  持】Hongqi Xu (Chief Scientist，BAQIS)

【题  目】Extreme spatiotemporal imaging and control of low dimensional structures to attosecond time and nanometer length scales

【摘  要】During the past decade unprecedented abilities to probe and exploit light-matter interaction down to the nanometer and attosecond spatiotemporal scales have emerged. This opens for new fundamental physical insights as well as to rationally design novel functional materials and devices with applications for energy harvesting, smart sensing, and alternative computing. We discuss the combination of femtosecond and attosecond time resolution of advanced laser systems with the nanoscale spatial resolution of PhotoEmission Electron Microscopy (PEEM) ^[1]. This can unravel the hot electron dynamics in 1D and 2D semiconductors ^[2,3] and the dynamics of near-field enhancement in hybrid metal-semiconductor nanostructures ^[4] and attosecond electron excitation dynamics ^[1,5]. A new setup for achieving extremely well characterized laserbeams in combination with photoelectron momentum and energy resolved microscopy will be presented that could be used for studying quantum materials and effects at ultrashort timescales. Finally, we discuss applications of nanophotonic concepts in an artificial neural network ^[6-8] in which the weighted connectivity between nodes is achieved by overlapping light signals inside a shared quasi 2D waveguide – a broadcasting concept. This decreases the circuit footprint by orders of magnitude compared to existing optical solutions employing nanoscale III-V components originally derived for photovoltaics and quantum technologies.

1. Vogelsang, J. et al.,  Attosecond microscopy - Advances and outlook, Europhysics Letters (2025)

2. Wittenbecher, L. et al., Unraveling the Ultrafast Hot Electron Dynamics in Semiconductor Nanowires, ACS Nano 15 (2021) 1133.

3. Kolesnichenko, P. V., et al., Sub-100 fs Formation of Dark Excitons in Monolayer WS2, Nano Letters 24 (2024 ), 14663-14670

4. Zhong, J.H.,et al,  Nonlinear plasmon-exciton coupling enhances sum-frequency generation from a hybrid metal/semiconductor nanostructure, Nature Comm. 11 (2020), 1

5. Vogelsang, J., et al,  Time-Resolved Photoemission Electron Microscopy on a ZnO Surface Using an Extreme Ultraviolet Attosecond Pulse Pair. Adv. Phys. Res., 3 (2024) 2300122.

6. Winge, D.O, et al. Artificial nanophotonic neuron with internal memory for biologically inspired and reservoir network computing, Neuromorph. Comput. Eng. 3 (2023) 034011

7. Alcer, D., et al. Integrating molecular photoswitch memory with nanoscale optoelectronics for neuromorphic computing. Commun Mater 6, 11 (2025).

8. Flodgren, V. et al, Direct on-Chip Optical Communication between Nano Optoelectronic Devices,  ACS Photonics (2025)

【报告人简介】Anders Mikkelsen (AM) studies the interplay between function, structure, and growth of nanostructures, from micrometers down to the atomic scale, from seconds to attosecond and moving towards realistic synthesis and device operation environments. The aim is a better fundamental understanding of complex, dynamic condensed matter systems, as well as developing novel materials and devices for next generation computing, energy systems and products improving our lives. A present focus is on using advanced light sources such as 4th generation synchrotrons and atto/femto second lasers in combination with high resolution microscopy and fabrication of nanoelectronic devices. AM has significant research and leadership experience on both a project level and in large interdisciplinary environments of combining expertise from across electronics, photonics, physics, chemistry, and biology. Has collaborated with both SMEs and major International Companies, most recently being granted a Vinnova CC that includes both large and small Swedish companies and goes across material science and digitalization.