ABSTRACT
In this chapter, the authors expect the response to skew rays in a rotationally symmetric 3D system to be nonideal just as in the all-reflecting case, and, in fact, ray-tracing of some sample lens-mirror configurations shows angular cutoff characteristics indistinguishable from the simple CPC counterpart. They describe a procedure in which an input surface and an output surface of given shapes are postulated, enclosing and surrounded by regions of given refractive index distributions. A more fundamental method for overcoming the disadvantage of excessive lengths incorporates refractive elements to converge the pencil of extreme rays. The author describes a procedure in which an input surface and an output surface of given shapes are postulated, enclosing and surrounded by regions of given refractive index distributions. They conclude with a discussion of a design prescription for optimal concentrators that historically has been a fertile source of new and useful solutions.
