InGaN-LD-Pumped Continuous-Wave Deep Red Laser at 670 nm in Pr3+:LiYF4 Crystal

We report the first laser operation at π-polarized 670.34-nm deep red laser in a 2-W InGaN-LD-pumped Pr³⁺:LiYF₄ (Pr:YLF) crystal with the aid of a 0.1-mm intracavity etalon, to the best of our knowledge. The maximum output power of this laser emission was up to 87.6 mW with slope efficiency of ~11.9$ % with respect to the absorbed pump power. The beam propagation factors in x-direction and y-direction were measured to be 1.49 and 1.05, respectively.