High-order harmonic generation in ZnO driven by a Laguerre-Gauss vortex beam

We theoretically investigate the high-order harmonic generation (HHG) process in a ZnO semiconductor crystal, driven by light beams carrying orbital angular momentum (OAM). Our studies focus on the transfer of OAM from the driving field to the harmonic field and the conservation of OAM in the strong-field regime. To this end, we combine the semiconductor Bloch equations with the thin slab model. This approach allow us to simulate the HHG process in semiconductor media and to compute the far-field properties of the generated harmonic fields. {{red} Our theoretical approach successfully reproduces key experimental features previously observed in ZnO when the driving field is a Laguerre-Gaussian beam}.