Marchand E W
Appl Opt. 1972 May 1;11(5):1104-6. doi: 10.1364/AO.11.001104.
There are two families of gradient-index functions of cylindrical type for which the differential equations of the rays can be completely integrated without any approximations. One of these has focusing properties within the medium and so can be considered for use in GRIN rods. Both examples can prove useful in the design of conventional types of optical systems involving gradient-index elements.
有两类柱面型梯度折射率函数，对于它们，光线的微分方程可以完全积分而无需任何近似。其中一类在介质内部具有聚焦特性，因此可考虑用于梯度折射率棒。这两个例子在涉及梯度折射率元件的传统光学系统设计中都可能有用。
