We demonstrated 22 W LD-pumped high-power continuous-wave (CW) deep red laser operations at 718.5 and 720.8 nm based on an a-cut Pr3+:YLF crystal. The output power of both polarized directions reached the watt-level without output power saturation. A single wavelength laser operated at 720.8 nm in the π-polarized direction was achieved, with a high output power of 4.5 W and high slope efficiency of approximately 41.5%. To the best of our knowledge, under LD-pumped conditions, the laser output power and slope efficiency are the highest at 721 nm. By using a compact optical glass plate as an intracavity etalon, we suppressed the π-polarized 720.8 nm laser emission. And σ-polarized single-wavelength laser emission at 718.5 nm was achieved, with a maximum output power of 1.45 W and a slope efficiency of approximately 17.8%. This is the first time that we have achieved the σ-polarized laser emission at 718.5 nm generated by Pr3+:YLF lasers.

High-power continuous-wave ultraviolet lasers are useful for many applications. As ultraviolet laser sources, wavelength switching capability and compact structure are very important to extend the applicability and improve the flexibility in practical applications. In this work, we present two simple and relatively compact schemes by laser diode pumping to obtain watt-level singlewavelength 348.7-nm laser and discrete wavelength tunable ultraviolet lasers around 349 nm (from 334.7 to 364.5 nm) by intracavity frequency doubling based on Pr 3+ :YLF and β-BBO crystal. The maximum output power of the singlewavelength 348.7-nm laser is 1.033 W. The output powers of the discrete wavelength tunable lasers are at the level of tens of milliwatts, except for two peaks at 348.7 and 360.3 nm with output powers of ~500 mW. In addition,

We report continuous-wave deep red lasers at 696.6 and 698.6 nm in a Pr 3 :YLF crystal pumped by an InGaN laser diode. A Lyot filter was inserted into the cavity as a birefringent filter to select wavelength; the lasers at 696.6 and 698.6 nm were obtained with a maximum output power of 1.36 and 3.11 W, separately. To the best of our knowledge, the output powers of these two lasers are the highest to date, and this is the first scaling of the output power of the Pr 3 :YLF laser to the watt level at around 696 nm. In addition, the corresponding theoretical analysis and simulation were carried out to explain the experimental phenomena.

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A CW laser in a Pr3+:YLF crystal at 729 nm is reported for the first time, to the best of our knowledge. Using an InGaN laser diode providing 24 W at ∼444 nm, a tuning range from 728.75 nm to 729.97 nm is obtained. A laser output power of up to 1.90 W at 729.46 nm is demonstrated. The output power fluctuation is stable within ±2% at 729.46 nm, and the beam quality Mx2 and My2 factors are measured to be 1.46 (x) and 1.40 (y).