Study on 1064 nm High-Purity, High-Beam-Quality Cylindrical Vector Beams Laser

To generate cylindrical vector beams (CVBs) with high mode purity and high beam quality, a polarization-maintaining fiber oscillator was built, followed by high-efficiency mode conversion with an S-waveplate. This system leverages the S-waveplate as a mode converter to transform the fundamental LP01 mode into radially and azimuthally polarized beams, which both feature a central polarization singularity. The experimental results demonstrate that the system successfully yielded a radially polarized beam with an output power of 3.93 W and a high mode purity of 96.99%, as well as an azimuthally polarized beam with an output power of 3.71 W and a mode purity of 96.5%. The corresponding beam quality factors (M2) were measured to be 2.17 and 2.01, respectively. After 60 min of continuous operation at maximum power, the radially and azimuthally polarized beams had average powers of 3.988 W and 3.785 W, with RMS stabilities of 0.788% and 0.590%, respectively. To the best of our knowledge, this represents the highest power reported to date for both radially and azimuthally polarized CVBs that simultaneously possess high mode purity and beam quality. This work provides an effective solution to obtain high-power CVB sources that simultaneously possess high mode purity and beam quality, establishing a solid foundation for subsequent power scaling and practical applications.