As yet, a variety of approaches, such as the perturbation method, power series expansion, angular spectrum representation and integral solution of the wave equation etc. have been proposed to treat the beam propagation behavior beyond the paraxial regime.

• 迄今已提出许多方法 ,例如微扰法、级数展开法、算子法、角谱分析法和波动方程积分解等方法 ,用以研究光束的非傍轴传输行为。