Generation of high-order Hermite-Gaussian modes and optical vortices by manipulating off-axis displacement of an intracavity lens.

Hermite-Gaussian (HG) modes and optical vortices (OVs) are crucial for advanced photonic applications. In this work, we demonstrate a more intuitive and precisely controllable intracavity approach compared with existing methods such as off-axis pumping, mirror tilting, and crystal tilting. By adjusting the off-axis displacement of a plano-convex lens, the astigmatism introduced into the cavity is precisely tuned. This allows the generation of continuous-wave HG0,n modes with tunable n from 0 to 24 in a compact laser-diode (LD) end-pumped Nd:YAG laser. Using an astigmatic mode converter (AMC), vortex beams with topological charge tunable from 1 to 24 are obtained and verified by interference patterns. This approach provides a direct and compact route to diverse structured beams for advanced optical systems.