Feature

The Optical Invariant Ii

Pat Trotta

In the last article on the optical invariant, we showed that an invariant exists between any two paraxial rays traced through an optical system (as long as the rays emanate from different object points). We also showed ways the invariant can be used to quickly establish an optical system concept, and ensure that nothing impossible was being attempted. In this article, we will show how the optical invariant, when combined with an optical system's paraxial raytrace, can conveniently lead to detailed first order analyses. As before, we will use an example to illustrate the methodology involved.