基于单晶光纤的单频连续波激光器研究进展OA

All-solid-state single-frequency continuous-wave lasers are high-quality light sources for fundamental research and application fields,including quantum optics,high-precision measurement,and so on owing to their intrinsic advantages of narrow linewidth,excellent beam quality,high power stability and low noise.With the rapid development of science and technology and the increasing demands of applications,it has become particularly important to scale up the output power of lasers while maintaining their overall performance. However,nonlinear effects become more and more severe with the increase of the output power for fiber lasers,and thermal effects are significantly enhanced under high pump power for rod crystal lasers.To address the limitations of fiber and rod crystal gain media,single-crystal fiber,a novel laser medium that combines the advantages of both,has become a more and more popular research hotspot in the field of all-solid-state lasers due to its excellent physicochemical properties,good thermal management characteristic,pump waveguide effect and high stimulated-Brillouin-scattering threshold.As is well known,scaling up the output power of the single-frequency continuous-wave laser is mainly implemented by means of a laser amplifier or a single resonator.This paper mainly focuses on the research progress of single-frequency continuous-wave lasers based on Nd∶YAG single-crystal fibers.A high-power linearly polarized single-frequency continuous-wave 1 064 nm laser based on the single-crystal fiber master oscillator power amplifier is presented,in which a 140 W low-noise single-frequency continuous-wave laser and an Nd∶YAG single-crystal fiber act as the seed laser and the laser medium of the master oscillator power amplifier,respectively.In order to obtain a high conversion efficiency,the mode-matching efficiency between the pump laser propagated with waveguide form and the freely propagated seed laser is optimized by considering the influence of the degradations of the polarization and the beam quality.When the incident powers of the pump and seed lasers are 262.6 and 126.3 W,respectively,the output power of the linearly polarized single-frequency laser reaches up-to 208 W.To the best of our knowledge,this is the highest output power based on an Nd∶YAG single-crystal fiber master oscillator power amplifier.In addition,a hybrid single-frequency continuous-wave 1 064 nm laser is presented,where both two Nd∶YVO4 bulk crystals and two Nd∶YAG single-crystal fibers are employed as gain media.By combining the advantages of the good thermal management characteristic of the Nd∶YAG single-crystal fiber with the natural birefringence effect of the Nd∶YVO4 bulk crystal,a stable single-frequency laser with high output power is achieved.Based on this scheme,a 120 W hybrid single-frequency continuous-wave 1 064 nm laser is obtained by employing Nd∶YAG single-crystal fibers as gain media in a single resonator. The presented laser technologies provide a good reference for achieving high-power single-frequency continuous-wave laser output at different wavelengths based on single-crystal fibers,which will strongly promote the development of laser technology and related fundamental research and application fields.