title: Aplanatic lenses revisited: the full landscape.
abstract: The full scope of solutions for dual-contour aplanatic lenses that can approach the basic limit for radiation transfer are identified, analyzed, and illustrated. Complementary solutions are shown to yield lenses that are either monolithic or have two refractive contours separated by an air gap. The performance of a promising representative design for LED collimation is presented.
authors.forename: Heylal
authors.initials: H
authors.lastname: Mashaal
authors.forename: Daniel
authors.initials: D
authors.lastname: Feuermann
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gordon