Ultrafast high-harmonic nanoscopy of magnetization dynamics

• Published in: Nature communications Vol. 12; no. 1; pp. 6337 - 8
• Main Authors: Zayko, Sergey, Kfir, Ofer, Heigl, Michael, Lohmann, Michael, Sivis, Murat, Albrecht, Manfred, Ropers, Claus
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.11.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 132/124; 639/301/357/997; 639/624/400/3923; 639/624/400/584; 639/638/298/920; 639/766/930/2735; Circular polarization; Dichroism; Dynamic structural analysis; Harmonic radiation; Humanities and Social Sciences; Hypothetical particles; Imaging; Light effects; Linear dichroism; Magnetic domains; Magnetism; Magnetization; multidisciplinary; Multilayers; Nucleation; Optical switching; Particle theory; Phase transitions; Radiation; Science; Science (multidisciplinary); Spatial discrimination; Spatial resolution; Spectroscopy; Spin dynamics; Temporal resolution
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-26594-0

Light-induced magnetization changes, such as all-optical switching, skyrmion nucleation, and intersite spin transfer, unfold on temporal and spatial scales down to femtoseconds and nanometers, respectively. Pump-probe spectroscopy and diffraction studies indicate that spatio-temporal dynamics may drastically affect the non-equilibrium magnetic evolution. Yet, direct real-space magnetic imaging on the relevant timescales has remained challenging. Here, we demonstrate ultrafast high-harmonic nanoscopy employing circularly polarized high-harmonic radiation for real-space imaging of femtosecond magnetization dynamics. We map quenched magnetic domains and localized spin structures in Co/Pd multilayers with a sub-wavelength spatial resolution down to 16 nm, and strobosocopically trace the local magnetization dynamics with 40 fs temporal resolution. Our compact experimental setup demonstrates the highest spatio-temporal resolution of magneto-optical imaging to date. Facilitating ultrafast imaging with high sensitivity to chiral and linear dichroism, we envisage a wide range of applications spanning magnetism, phase transitions, and carrier dynamics. Light induced magnetization dynamics can be as fast as few tens of femtoseconds. Here, Zayko et al show ultrafast microscopy based on high-harmonic radiation for direct imaging of ultrafast phenomena and capture femtosecond spin dynamics at the nanoscale.