Speaker
Description
The development of structured ultrafast laser sources has been crucial for advancing our understanding of the fundamental dynamics of electronic and spin processes in matter. In particular, ultrafast laser pulses structured in their spin angular momentum (linked to light polarization) and orbital angular momentum (related to the transverse phase profile or vorticity of a light beam) play a relevant role in studying chiral systems and magnetic materials at their intrinsic temporal and spatial scales.
Recent advancements have enabled the generation of structured ultrafast laser pulses on attosecond timescales, leading to significant progress in nonlinear optics. Specifically, the highly nonlinear process of high harmonic generation (HHG)—which up-converts an intense infrared driving beam into the extreme-ultraviolet (EUV) or soft X-ray region—now allows the creation of structured light pulses at the attosecond timescale.
This talk will review key developments in the field of attosecond structured pulses over the past decade [1-4], with a special focus on the up-conversion of spatiospectral and spatiotemporal optical vortices [5]. These beams are particularly well-suited for probing ultrafast electronic dynamics in systems with coupled spatial and temporal responses. We shall explore potential applications of these structured attosecond pulses in investigating localized ultrafast phenomena across fundamental and applied science.
[1] C. Hernández-García, A. Picón, J. San Román, and L. Plaja “Attosecond extreme ultraviolet vortices from high-order harmonic generation” Phys. Rev. Lett.111, 083602, (2013).
[2] A. K. Pandey, et al., ACS Photonics 9 (3), 944-951 (2022)
[3] A. de las Heras, D. Schmidt, J. San Román, J. Serrano, J. Barolak, B. Ivanic, C. Clarke, N. Westlake, D. Adams, L. Plaja, C. G. Durfee, C. Hernández-García, “Attosecond vortex pulse trains”, Optica 11, 1085 (2024).
[4] 4 N J. Brooks, A. de las Heras, B. Wang, I. Binnie, J. Serrano, J. San Román, L. Plaja, H. C. Kapteyn, C. Hernández-García, M. Murnane, “Circularly Polarized Attosecond Pulses enabled by an Azimuthal Phase and Polarization Grating”, ACS Photonics 12, 1, 495–504 (2025).
[5] R. Martín-Hernández, G. Gui, L. Plaja, H. K. Kapteyn, M. M. Murnane, C.-T. Liao, M. A. Porras and C. Hernández-García. “Extreme-ultraviolet spatiotemporal vortices via high harmonic generation” Nature Photonics, in press (2025).
