准三能级固体激光器热透镜效应模拟

Simulation of thermal lensing effect of quasi-three-level solid-state lasers

为了研究准三能级条件下固体激光器的热透镜效应,采用轴对称分布的晶体,泵浦光以高斯光束形式垂直端面射入晶体.分析出谐振腔的等效构图,然后利用ABCD光学传输矩阵理论模拟出谐振腔的稳定范围.在晶体内部散热均匀情况下,模拟了晶体内部温度的三维分布,计算晶体的热透镜焦距.利用数学物理方法解出晶体在不同功率和光斑半径下晶体内部的温度分布,并且计算出热透镜焦距的大小.利用MATLAB进行数据处理和数值计算,研究泵浦功率和泵浦光斑半径对热透镜焦距的影响.

In order to study the thermal lensing effect of solid-state lasers under quasi-three-level conditions,adopts an axisymmetric distribution of crystals,and pump light is injected into the crystal in the form of a Gaussian beam in the vertical end face.The equivalent composition of the resonator is analyzed,and then the stable range of the resonator is simulated by ABCD optical transmission matrix theory.Under the condition that the heat dissipation inside the crystal is uniform,the three-dimensional distribution of the temperature inside the crystal is simulated,and the thermal lens focal length of the crystal is calculated.The temperature distribution inside the crystal under different powers and spot radii is solved by mathematical and physical methods,and the focal length of the thermal lens is calculated.MATLAB was used for data processing and numerical calculation to study the influence of pump power and pump spot radius on the focal length of thermal lens.