Controllable multi-polarization laser beam generation and manipulation in a cylindrical cavity

The manipulation of spatial and polarization attributes in vector laser beams can be intricately controlled through a variety of methodologies including spatial light modulators, q-plates, optical cavities, and mode-selective coupling. Among these techniques, optical cavities exhibit notable merits as they enable the targeted amplification of desired polarization elements with significant efficiency and stability. This research article introduces a direct methodology to generate multiple polarized laser beams, leveraging a cylindrical laser cavity housing a birefringent c-cut Nd:YVO₄ gain crystal. This technique facilitates the creation of Hermite-Gaussian modes exhibiting distinct polarization states. By exploiting specific geometrical arrangements involving optical Z-mode and W-mode, the degenerate laser cavity facilitates the concurrent production of numerous distinguishable elliptically and linearly polarized beams, obviating the necessity for supplementary optical components. Notably, this approach provides advanced control over the polarization of resulting beams through precise adjustments of pumping offset and cavity length. The polarization states are subjected to quantitative scrutiny through phase retardation analysis. This investigation introduces an innovative avenue for the generation of coherent multi-beams, thereby propelling progress across a wide spectrum of scientific and technological domains.