Watt-level all-solid-state single-frequency Pr:LiYF4 ring laser in the orange spectral region with wavelength tunability

In this work, we report on the recent research progress on watt-level all-solid-state single-frequency Pr:LiYF 4 (YLF) lasers in the orange spectral region.Combining dual-end pumping and ring-cavity technologies, we have achieved a maximum singlefrequency output of 1.19 W at 607 nm with a linewidth of about 20.3 MHz.Based on this study, by inserting a 0.15 mm etalon inside the ring cavity, we find that the 607 nm lasing can be completely suppressed and a single-frequency laser at 604 nm with a 0.69 W output power and a linewidth of about 16.7 MHz can also be obtained.Moreover, the wavelengths of the two single-frequency lasers can be tuned from 607.16 to 607.61 nm and from 603.99 to 605.02 nm, respectively.Furthermore, the single-frequency Pr:YLF laser can also operate in a state of the two orange wavelengths, simultaneously, with a maximum output power of 0.97 W. We believe that this is the highest output power of a direct generation of single-frequency orange lasers and the first demonstration of the wavelength-tuned operation of the achieved single-frequency orange lasers, which could bring opportunities for the application of single-frequency orange lasers.