Research On Narrow Linewidth Tm:YLF Laser Pumped By LD

2?m eye-safety laser is located in the atmospheric window,widely used in laser medical,environmental monitoring and optical communication,etc.In addition,it can be used as3~5?m and 8~12?m in the infrared optical parametric oscillator and photoparametric amplifier pumping source.Doped Ho3+ crystal is the preferred working material for producing high-performance 2?m laser,while 1.9?m Tm: YLF laser is the ideal pumping source.Therefore,it is important to obtain high power,high efficiency and high stability of1.9?m laser output.In this paper,the experiment is based on the theoretical simulation,with the volume bragg grating as the resonator and the intracavitary double F-P etalons,the narrow linewidth laser output can be obtained on the basis of high power and high stability.Theoretically,Theoretically,the physical and spectral characters of Tm:YLF crystal are introduced.Based on the Tm:YLF laser quasi-three-level rate equation model,the expressions of laser threshold,output power and slope efficiency are obtained by simplifying the equations,and simulation analysis the effects of upconversion effect,cross-polarized,and crystal doping concentration and length on the output characteristics of Tm:YLF lasers,which lays a theoretical foundation for the design and experiment of subsequent lasers.Design aspects,based on the thermal model of Tm:YLF crystal,the distribution of crystal temperature field is deduced and the thermal distribution of each parameter is simulated,then the crystal of size 3×3×12mm3and the doping concentration of 3.5at.%adopted;The parameters range of the “L” resonator is designed,which is the basis for the follow-up experimental study.The parameters of the volume bragg grating and the F-P etalon are designed,and the parameters of the resonator are selected.The end face size of the grating is 6×6mm2,the thickness is 5.5±1.5nm,and the thickness of the double F-P etalons are 0.1mm and 1mm respectively.Experimentally,the LD end-pumped Tm: YLF lasers were set up,and the effects of different resonant cavity length,output mirror transmittance and radius of curvature on the output characteristics of the laser cavity were studied in order to determine the best resonant cavity parameters.And the double F-P etalons were inserted into the cavity.The 17.8W1908.55 nm laser with high stability was obtained.The linewidth was only 0.10 nm,and the maximum wavelength fluctuation range was only 0.34 nm.The corresponding slope efficiency and light-to-light conversion efficiency of the laser are 42.89% and 35.86%,respectively.