Carlos Hernandez-Garcia
The advancement of structured ultrafast laser sources is critical for unraveling the fundamental dynamics of electronic and spin processes in matter. Twisting light pulses at the attosecond timescale, which incorporate structured light with spin angular momentum (SAM) and orbital angular momentum (OAM), are proving to be essential for probing chiral systems and magnetic materials at the natural timescales of laser-driven electronic dynamics. Recent progress in generating high-frequency structured pulses in the extreme-ultraviolet (EUV) has opened new frontiers in nonlinear optics through high-harmonic generation (HHG). By transferring light’s angular momenta from infrared drivers to high-frequency radiation, HHG enables the generation of twisted light beams with unique properties.
In this talk, we review our recent advancements in generating structured coherent EUV pulses at the attosecond timescale through HHG. Since the early work on HHG driven by vortex beams, utilizing driving field configurations with custom OAM has opened new opportunities for controlling high-order harmonic properties [1,2]. Notable advancements include the generation of attosecond vortices with controlled polarization [3], high harmonic pulses with time-dependent OAM or self-torque [4], EUV vector harmonic pulses [5], spatially-structured harmonic beams from graphene [6], attosecond vortex pulse trains (Fig. 1) [7] or EUV spatiotemporal and spatiospectral optical vortices [8].
1 C. Hernández-García et al. “Attosecond Extreme Ultraviolet vortices from high-order harmonic generation”, Physical Review Letters 111, 083602 (2013).
2 C. Hernández-García, “A twist in coherent X-rays”, Nature Physics 13, 327-329 (2017).
3 K. M. Dorney, et al. “Controlling the polarization and vortex charge of attosecond high-harmonic beams via simultaneous spin-orbit momentum conservation”. Nat. Photon. 13, 123-130 (2019).
4 L. Rego, K. M Dorney, N. J Brooks, Q. Nguyen, C.-T. Liao, J. San Román, D. E Couch, A. Liu, E. Pisanty, M. Lewenstein, L. Plaja, H. C Kapteyn, M. M Murnane, C. Hernández-García “Generation of extreme-ultraviolet beams with time-varying orbital angular momentum”. Science 364, eaaw9486 (2019).
5 C. Hernández-García, A. Turpin, J. San Román, A. Picón, R. Drevinskas, Ausra Cerkauskaite, P. G. Kazansky, C. G. Durfee, and I. J. Sola, “Extreme ultraviolet vector beams driven by infrared lasers”, Optica 4, 520-526 (2017).
6 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).
7 A. García-Cabrera, R. Boyero-García, O. Zurrón-Cifuentes, J. Serrano, J. San Román, L. Plaja, and C. Hernández-García, “Topological harmonic spectroscopy”, Communications Physics 7, 28 (2024).
8 R. Martín-Hernández, G. Gui, L. Plaja, H. Kapteyn, M. Murnane, C.-T. Liao, M. A. Porras and C. Hernández-García, “High-topological charge extreme-ultraviolet spatiotemporal vortices via high harmonic generation, ”Preprint: : https://doi.org/10.21203/rs.3.rs-4779794/v1