Study on the Generation of 1.9 m Mode Superposition Conversion Laser by Double-End Off-Axis Pumping

In this paper, the Laguerre-Gaussian (LG) mode superposition is obtained by using the technology of double-end off-axis pumping Tm:YLF crystal, and the LG mode superposition is achieved by combining the extra-cavity conversion method. The impact of changing the off-axis distance on the order of Hermite-Gaussian (HG) mode and the topological charge of LG mode is studied. The results show that when the off-axis distance of the pump source at both ends is tuned, when the off-axis distance is in the range of 260 mu m similar to 845 mu m, the single-ended 0 similar to 10 order HG mode can be obtained. Subsequently, the mode converter is placed to obtain the LG mode beam, and the double-end simultaneously pumps the crystal to obtain the superimposed LG mode. The tuning off-axis quantity changes the topological charge number. When P = 0, l(1)=l(2), the superimposed LG mode is a single-ring spot, and the vortex beam center's dark hollow area increases with the topological charge number. When P = 0, l(1)=-l(2), the superimposed LG mode is a petal-like spot. The number of petals differs from the topological charges of two opposite numbers. Finally, in the case of changing the topological charge number of the double-ended LG mode, the output of the vortex array structured beams of the tuning mode order 1.9 mu m Tm:YLF is completed in the case of conversion and superposition.