Design of optimal and ideal 2-D concentrators with the collector immersed in a dielectric tube

Abstract
In this paper we present a method for designing ideal and optimal 2-D concentrators when the collector is placed inside a dielectric tube for the particular case of a bifacial collector. The method, based on the extreme ray principle of design, avoids the use of differential equations by means of a proper application of Fermat's principle. One advantage of these concentrators is that they allow the size to be small compared with classical CPCs.