Description
Solid-state platforms underpin modern electronics, yet how intense ultrashort light pulses carrying orbital angular momentum (OAM) interact with solids remains largely unexplored. By contrast, conventional light–matter interactions are often described well within the dipole limit, with electron dynamics being confined to a single Brillouin zone. Progress has been limited by the technical challenge of generating intense ultrashort vortex pulses, particularly in the mid-infrared regime. As a result, the role of structured light in driving nonlinear, non-perturbative processes in solids, and the associated transfer of angular momentum during these interactions, has not been systematically explored. We investigate solid-state high harmonic generation (HHG) driven by intense ultrashort structured light using a versatile experimental approach applicable to different materials and geometries. We demonstrate that the OAM of the driving field is coherently transferred to the generated harmonics. In particular, we show that the OAM is conserved independently of the crystal symmetry, the range of electronic interactions, and the presence of strong spin-orbit coupling. These results establish OAM-resolved HHG as a robust framework for characterizing and controlling angular momentum transfer in solid-state HHG and open new avenues for structured-light-driven quantum technologies and topological materials investigations.
