Ultrafast high-harmonic nanoscopy of magnetization dynamics

Abstract

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 timescale 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 observe the reversible and irreversible evolution of nanoscale spin textures following femtosecond laser excitation. Specifically, 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 approach enables the highest spatio-temporal resolution of magneto-optical imaging to date. Facilitating ultrafast imaging with an extreme sensitivity to various microscopic degrees of freedom expressed in chiral and linear dichroism, we envisage a wide range of applications spanning magnetism, phase transitions, and carrier dynamics.

14 pages, 4 figures

References in corpus (7)

• X-ray image reconstruction from a diffraction pattern alone
• Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
• Ultrafast, ultrabright, X-ray holography using a uniformly-redundant array
• Ultrafast nano-imaging of the order parameter in a structural phase transition
• Kibble-Zurek mechanism in a quenched ferromagnetic Bose-Einstein condensate
• A light induced metastable magnetic texture uncovered by in-situ Lorentz microscopy
• Magneto-Optical Functions at the 3p resonances of Fe, Co, and Ni: Ab-initio description and experiment

Cited by in corpus (5)

• Attosecond magnetization dynamics in non-magnetic materials driven by intense femtosecond lasers
• All-optical switching on the nanometer scale excited and probed with femtosecond extreme ultraviolet pulses
• Ultrafast element- and depth-resolved magnetization dynamics probed by transverse magneto-optical Kerr effect spectroscopy in the soft x-ray range
• Three-dimensional tomographic imaging of the magnetization vector field using Fourier transform holography
• Analyser-free, intensity-based wide-field magneto-optical microscopy