title: Design Of nonimaging concentrators as second stages in tandem with image-forming first-Stage concentrators.
abstract: We show how paraboloidal mirrors of short focal ratio and similar systems can have their flux concentration enhanced to near the thermodynamic limit by the addition of nonimaging compound elliptical concentrators.
authors.forename: R
authors.initials: R
authors.lastname: Winston
authors.forename: W T
authors.initials: WT
authors.lastname: Welford