Fig. 1. Experimental setup of the all-solid-state single-frequency orange laser. HWP: half-wave plate; FR: Faraday rotator; E: etalon.

Fig. 2. Polarization-dependent emission cross sections of a Pr³⁺-doped YLF crystal using InGaN LD as the excitation source.

Fig. 3. Output power versus pump power of the single-wavelength single-frequency laser at 607 nm. Inset, optical spectrum of the single-frequency laser.

Fig. 4. Spectrum of the single-wavelength single-frequency laser at 607 nm measured with an F–P scanning interferometer.

Fig. 5. Power stability of the single-wavelength single-frequency laser at 607 nm within 20 min.

Fig. 6. Beam quality measurement of the 607 nm single-frequency laser.

Fig. 7. Transmission of the etalon at different refraction angles.

Fig. 8. Output power versus pump power of the single-wavelength single-frequency laser at 604 nm. Inset: optical spectrum of the single-frequency laser.

Fig. 9. Spectrum of the single-wavelength single-frequency laser at 604 nm measured with an F–P scanning interferometer.

Fig. 10. Power stability of the single-wavelength single-frequency laser at 604 nm within 20 min.

Fig. 11. Wavelength tunabilities of the single-wavelength single-frequency laser at 607 and 604 nm.

Fig. 12. Output power versus pump power of the dual-wavelength single-frequency laser. Inset, optical spectrum of the single-frequency laser.

Fig. 13. Spectrum of the dual-wavelength single-frequency laser measured with an F–P scanning interferometer.