Fig. 1. Schematic of the diode-pumped wavelength-switchable CW visible Pr³⁺: YLF laser around 670 nm

Fig. 2. Experimental results of single-wavelength lasers around 670 nm. (a) Output powers and slope efficiencies with respect to absorbed pump powers. (b) Laser output spectra at 670.4 nm, 674.2 nm, and 678.9 nm, respectively. (c) Measured corresponding M² factors of 670.4 nm, 674.2 nm, and 678.9 nm, respectively. (d) Power stabilities of lasers at 670.4 nm, 674.2 nm, and 678.9 nm

Fig. 3. Emission cross sections of Pr³⁺:YLF crystal around 670 nm under room temperature.

Fig. 4. Simulation results of the input-output power characteristics at 670 nm. BR is the waist beam radius of the laser; SE is the slope efficiency. 0.103 mm is the smallest beam radius which can be obtained by the cavity parameters.

Fig. 5. (a) Output characteristics of dual-wavelength lasers around 670 nm, i.e., 670.1/674.8, 670.1/679.1, 675.0/679.4 nm, respectively. (b) Laser output spectra of dual-wavelength lasers measured at the maximum output powers of 2.52, 1.80, and 0.36 W, respectively. (c) Laser output spectra of triple-wavelength lasers measured at the output powers of 1.78 and 0.84 W, respectively. (d) Power stabilities of the dual-wavelength lasers. (e) Power stabilities of the triple-wavelength lasers.

Fig. 6. (a) Output performance of the visible vortex laser at 670.4 nm ( and modes). (b) Measured laser beam spots and the corresponding spiral interference patterns. (c) Laser spectrum of the vortex lasers (the spectra of the different LG modes were the same).

Table 1. Parameters used in the simulation. 2γ_in is the total intracavity logarithmic round-pass loss.