Nonimaging optics

Summary

Nonimaging optics is the part of geometrical optics that designs systems to transfer light from a source to a target. The aim is efficient transfer, not the formation of an image. Typical goals are to concentrate sunlight onto a small absorber or to spread the light of a lamp evenly over a surface. Its basic tool is the conservation of etendue, which gives an upper bound on how strongly light can be concentrated. Designs such as the compound parabolic concentrator reach this bound in two dimensions.