Study On Performance Of Diode Side-pumped Slab Laser

In order to optimize the beam quality of high-power slab lasers,when the crystal size and pumping conditions are limited,the size of the single-sided fundamental mode beam can be increased to limit the oscillation of the higher-order modes in the cavity,so as to improve the quality of the laser beam.Based on the above ideas,this thesis studies the beam quality improvement of diode side-pumped slab lasers.In this thesis,the structural design,theoretical simulation and experimental research of LD side-pumped slab laser are carried out.The thermal focal length of the laser in the horizontal and vertical directions of the pump is measured,and the thermal lens equivalent model is established.The simulation of the equivalent cavity stability and the cavity mode spot radius is carried out.After simulating the calculation of various cavity types.A comparative experimental study was carried out on the flat cavity and the flat cavity structure.Theoretical analysis shows that the horizontal and vertical directions of the fundamental mode beam on the side of the crystal end face are larger than that of the flat cavity.The experimental results show that the thermal focal lengths in the width direction and the height direction are 99.4 mm and 327.7 mm,respectively,when the pump electric power is 1030 W.When the same pump current is 20A input and the cavity length is 370mm,the output power of the flat cavity is 59.9W,which is slightly smaller than the 101.2W of the flat cavity.However,the M~2 factor of the output beam horizontal direction is significantly optimized from 115.6 to 32.9,and the vertical direction M~2 factor is significantly optimized from 116.4 to 60.9.This thesis verifies that the expansion of the single-sided fundamental mode size can limit the high-order mode to optimize the beam quality,and proposes the research direction to further optimize the performance of the slab laser.At the same time,as the actual number of oscillation modes decreases,the crystal utilization rate decreases,causing the output power to decrease.This research has practical significance for the high-quality output and related applications of the slab laser output.