Double End Pumped Pr:YLF Narrow Linewidth Green Laser

Narrow linewidth laser has the advantages of narrow linewidth,strong stability,low noise,good coherence and good beam quality,which plays an important role in high resolution Raman spectroscopy,Doppler wind radar,optical communication and holography.In this paper,the green laser output is directly realized by Pr:YLF crystal specificity,which reduces the complexity of the temperature control system due to the frequency doubling crystal itself.On this basis,by introducing the double F-P standard to the cavity,the longitudinal mode laser in the cavity has a specific loss,and the longitudinal mode corresponding to the wavelength frequency has a low loss to achieve oscillation,while the other modes near the center mode are effectively suppressed due to high loss,so as to realize the 522 nm narrow linewidth laser output.In theoretical research,the theoretical model of narrow linewidth green laser with double F-P standard loss and output mirror transmission loss is established.The four-level rate equation with multiple losses is solved,and the output characteristics of the Pr:YLF narrow-linewidth green laser are simulated.The effects of intracavity photon density,inversion particle number density and output power on the transmittance of the output mirror are obtained.On this basis,the influence of the placement angle of the double F-P standard on the output characteristics of Pr:YLF narrow linewidth green laser is obtained by theoretical analysis of the mode selection technology of the double F-P etalons.Therefore,the thickness of the double F-P standard is 0.3mm and 0.5mm,and the optimal angles are 1.42 °and 0.69°,which lays a theoretical foundation for experimental research.In addition,the ABCD matrix is used to simulate the stable region of the laser and the waist size and position of single-end and double-end pump crystals,and the optimal parameters of the experiment are determined.In the experimental research,the single-end-pumped Pr:YLF experiment was first carried out,and the threshold power of 522 nm laser output was 795 m W.At this point,when the absorption power is 2.475 W,413m W of 522 nm laser output is obtained.In the dual-end pumped Pr:YLF experiment,when the absorption power was 5.023 W,577m W of 522 nm laser output was obtained,and the spectral linewidth was measured to be 0.83 nm.In the experiment of dual-end pumped Pr:YLF stable output,the double F-P etalons with different thicknesses is introduced into the cavity to obtain the narrow linewidth of 522 nm laser output.The threshold power of the laser is 2.559 W,and the maximum output power is53 m W.The F-P interferometer is used to verify that the single longitudinal mode output is at this time,and the spectral linewidth is measured to be 18 MHz.Through the comparative analysis of the experimental results and the theoretical simulation results,it can be seen that the experimental results are highly consistent with the theoretical results.It indicates that the theoretical model of Pr:YLF narrow-linewidth green laser established in this paper can reasonably and accurately describe and explain the internal operation behavior of Pr:YLF narrow-linewidth green laser.