four-level laser rod是什么意思

用法例句

The expression for the output input relation of a four level laser is obtained with the spatial distributions of the intracavity beam intensity and the inversion population density and the level splittings within the upper and lower level manifolds being taken into account.

得到了考虑腔内光强及反转粒子数密度的空间分布以及激光上、下能级组中能级分裂情况下四能级激光器输入输出关系的表达式 ,该表达式与以往得到的理论结果相比其精度有较大程度的提高。