针对角抽运复合板条激光器提出了一种新颖的热焦距计算方法。考虑到传统计算方法中一般采用均匀分布或指数衰减分布来表征热源分布，计算出的热焦距与实验值相差较大，不利于腔型设计的情况，采用Tracepro光学追迹软件追迹抽运光被耦合进入板条角面后，经过多次全反射在激光介质内传播的全过程，得到激光介质内热源的精确分布，求解稳态温度分布，再求出热透镜焦距。采用新方法计算出的热焦距与实验结果吻合良好，精确度明显高于传统方法。新方法简单实用，普适性强，可广泛应用于其他各类常见固体激光器。

A novel method to calculate the thermal focal length of corner-pumped slab lasers is proposed. Traditional methods generally use uniform distribution or exponential decay distribution to characterize the heat distribution, and the difference between calculation results and the experimental value is not small which is against the further cavity design. Tracepro software is used to trace the pump light in the medium so as to get the accurate heat distribution within the gain medium, and then the temperature distribution and thermal focal length is calculated. The calculation results of this method are according with experiments much better than those of the traditional. This method is of general applicability, and is especially suitable for lasers with novel pump ways and special shape gain media.