First single-frequency Pr:LiYF4 ring laser at green

Short wavelength single frequency lasers are mostly indirectly achieved through a combination of single frequency laser technology and nonlinear frequency doubling. This work applies the ring laser cavity technology to the study of Pr3+ single frequency laser generation, for the first time to the best of our knowledge. Using a blue diode laser as pump source and Pr:YLF crystal as laser gain medium, we have directly achieved an all-solid-state short wavelength single frequency laser at green with a maximum output power of 0.52 W and a beam quality close to the diffraction limit. Pr3+ ions have a rich emission range in visible spectral region, and ring cavity technology is a mature commercial high-power single frequency laser technology. Therefore, it is expected that through this method demonstrated in this work, a series of simple, compact and stable single frequency laser sources operating in visible can be achieved for potential applications.