6 THE FLOW-LINE METHOD FOR DESIGNING NONIMAGING OPTICAL SYSTEMS
6.1 THE CONCEPT OF THE FLOW LINE
We have seen that the edge-ray approach to nonimaging concentration has considerable flexibility in handling 2D problems. Its application in 3D is more limited, and, although useful designs are obtainable in 3D, these fall short of ideal concentration. This motivates the search for alternatives to edge-ray designs, especially in 3D applications (Winston and Welford, 1979a).
In the geometrical optics approximation, we describe the propagation of light rays as trajectories in a six-dimensional phase space (p, x), where the components of x are the generalized coordinates (xl, x2, x3) and the components of p are the generalized momenta. These momenta ...