Light Topology Interplay in High Harmonic Generation from Graphene

Structured laser beams-coherent light beams with nontrivial spatio(temporal) distributions of polarization, phase or intensity-have emerged as unique tools to unravel the electronic dynamics at the ultrafast and nanometric scales. A paradigmatic example is high-order harmonic generation (HHG) driven by structured beams, whose deep understanding has triggered the emergence of a wide variety of high-frequency structured laser sources with light topologies that evolve at ultrafast timescales [1]. HHG has been mainly studied in atomic and molecular gases, but recent experiments performed in solids have stimulated the exploration of non-perturbative electronic dynamics in crystals. Crystalline solids stand out as targets for HHG not only because of their higher electronic density-leading to better efficiency of the harmonics-but also due to their characteristic symmetries, which introduce distinctive ultrafast phenomena, such as the matter-Talbot effect [2] or the anisotropic HHG [3], [4].