Speaker
Description
In lightwave electronics, optical carrier fields act as alternating voltages to accelerate electrons within less than a cycle of light. This way, crystal electrons can move without scattering, unleashing an all-coherent quantum world full of promise for future quantum technologies [1].
Subcycle dynamics, such as Bloch oscillations, quasiparticle collisions, and spin-polarized topological currents [2] manifest in high-harmonic and high-order sideband generation. Subcycle photoelectron spectroscopy can visualize the underlying dynamics with direct band-structure videography, resolving ballistic motion of Dirac currents and Floquet-Bloch band engineering [3]. By combining this idea with photoelectron momentum microscopy, we can image subcycle electron dynamics throughout the entire first Brillouin zone of essentially any quantum material [4]. Moving from momentum space to real space, lightwave-driven scanning tunnelling microscopy (STM) can videotape single molecules [5] and atomic defects [6] and observe the subcycle quantum flow of electrons [7]. By biasing the STM junction with phase-controlled single-cycle near-infrared light pulses, we combine attosecond temporal with atomic spatial resolution, for the first time [8]. Our results offer a radically new way of watching and controlling elementary quantum dynamics in condensed matter at the space-time limit.
[1] Borsch et al., Nat. Rev. Mater. 8, 668 (2023), Kira et al., Opt. & Photon. News 36, 28 (2025)
[2] Schmid et al., Nature 593, 385 (2021), Freudenstein et al., Nature 610, 290 (2022), Riepl et al., under review
[3] Ito et al., Nature 616, 696 (2023), Reimann et al., Nature 562, 396 (2018)
[4] Eggers et al., arXiv:2602.12844, under review
[5] Cocker et al., Nature 539, 263 (2016), Peller et al., Nature 585, 58 (2020)
[6] Roelcke et al., Nature Photon. 18, 595 (2024)
[7] Siday et al., Nature 629, 329 (2024)
[8] Maier et al., arXiv:2507.10206, accepted in principle