Study of high beam quality side-pumped Nd:YLF laser with intracavity Gaussian aperture

In order to obtain a 1053 nm output laser with a high beam quality, the mode distribution of the YLF solid laser with a plane-plane resonator is studied. According to the Collins theory, the influences of the position and size parameters of a Gaussian aperture on the mode of the output beam is simulated and analyzed. Compared with the simulation results without a Gaussian aperture, the Gaussian aperture in the cavity can significantly improve the quality of the output laser. Based on the theoretical simulations, a laser with optimal structural parameters is built. The profiles and mode distributions of the laser output beams with a Gaussian aperture and without a Gaussian aperture in the cavity are measured, respectively. When the radius of the light spot on the film of the Gaussian aperture is 4 mm and the distance between the Gaussian aperture and total-reflection mirror is 30 mm, a 1053 nm laser output with the values of M2 in the x and y directions of 1.9 and 1.8, and maximum output power of 9.7 W is obtained. The experimental results demonstrate that the Gaussian aperture in the cavity can improve the mode distribution of the cavity and obtain the laser output with a higher beam quality, which is basically consistent with the results of theoretical simulations.