Finite Element Technique based on Rayleigh-Ritz idea is used to solve wave propagation in non-homogeneous medium with variable velocities. 為求解變速不均勻介質(zhì)中波的傳播問題，使用了利用瑞雷-里茲法的有限元技術(shù)。
Then the displacement field in homogeneous medium is considered the result of the first iteration, and the displacement field is solved by this integral equation. 然后，在均勻介質(zhì)中的位移場被認為是在第一次迭代的結(jié)果，和由這個積分方程求解的位移場。
The use of the method is not limited to simple lenses with gradient indices. It can also be used conveniently in the design of systems having homogeneous-medium elements. 這種設(shè)計方法不僅對于單片軸向梯度折射率透鏡，而且對于同時包括均勻介質(zhì)元件的光學系統(tǒng)也是很方便的。