Generating vector beams by modulating and superimposing multiple polarization modes within a helium-neon resonant cavity

In recent years, vector beams, which have greater control freedom due to their non-uniform spatial polarization distribution, have received extensive attention from scholars. In this paper, we present a straightforward intracavity modulation method by increasing the volume of the gas gain medium inside the cavity to induce multimode oscillation. Subsequently, Brewster windows and a curved-output mirror are used to achieve polarization control and superposition of multiple modes within the cavity to generate stable and controllable vector beams. In addition, the polarization purity of the radial vector beam and the angular vector beam can reach 87.98% and 85.52%, respectively. This work can not only break the understanding of the traditional vector beam generation method and deepen the understanding of laser cavity regulation technology but also play a guiding role in designing compact vector lasers.