1128W Continuous-Wave Single-Mode Green Laser Output by Frequency Doubling of a Linear-Polarization Narrow-Linewidth $1\mu \mathrm{m}$ Fiber Laser

Based on phase-modulated single-frequency seed technology, we have achieved 1925W high-power near-infrared single-mode laser output from a polarization-maintaining narrow-linewidth Yb-doped fiber laser. Furthermore, by employing a single-pass frequency-doubling method, we have obtained 1128W of continuous single-mode green light output, with a frequency-doubling efficiency of 58.6% and an output beam quality factor $\mathbf{M}^{\wedge}\mathbf{2}$ of 1.05. This represents the highest frequency-doubling efficiency reported to date for high-power single-mode continuous-wave green light output achieved through a single-pass frequency-doubling scheme.