Anomalous vortex beam driven harmonic generation

The generation and control of the properties of light beams carrying orbital angular momentum is fundamental to extend our understanding on the light-matter interaction process. In this letter, we investigate the use of anomalous and modified anomalous vortex beams for the generation of high-order harmonics (HHG) of the fundamental field. We demonstrate that by controlling the order and topological charge (TC) of the driving field, one can control the vortex beam size of the generated harmonics. A key outcome of this control is the ability to drive the HHG process with fundamental beams of higher TCs and consequently generating harmonics with higher TCs ($\approx 100$) while maintaining a compact beam size and nearly uniform divergence in the far-field across a wide range of harmonic orders.