在所有激光二极管(LD)侧面抽运的固体激光器的输出功率曲线中都存在一个平缓区域。通过对径向和切向热透镜焦距的理论计算, 发现平缓区域出现在径向稳区边缘, 在平缓区之后输出功率将继续升高, 并在切向稳区边缘达到最大值, 此时M2理论值最小。得出平缓区是由径向、切向稳区的共同作用导致的, 并且在切向稳区边缘可以实现高亮度激光器的结论。基于以上理论分析, 设计了一个具有简单平-平腔结构、LD侧面抽运的Nd:YAG高亮度激光器。实验中采用短腔型, 并使其工作在稳功率点, 当腔长为200 mm, 入射的抽运光功率为220 W时, 获得了输出功率为50 W, M2理论值为2的高亮度1064 nm连续激光输出。

Gentle zones were found in all output power curves of laser-diode (LD) side-pumped solid-state lasers. Through the calculation of the radial and tangential thermal lens effect, the gentle zones were found at the boundary of the radial stability zones, going through the gentle zone, the output power increased continuously and reached its highest value at the boundary of the tangential stability zone with the lowest M2 value. The gentle zones were thought to be due to the combined effects of the radial and tangential stability zones and high-brightness lasers can be obtained at the stable power point. Based on this, a simple high-brightness laser with a cavity length of 200 mm was designed to operate at the boundary of the tangential stability zone, and laser at 1064 nm with output power of 50 W and theoretical beam factor M2=2 was achieved when the pump power was 220 W.