title: Envelope mirror: a new concept of focusing reflecting optics.
abstract: A mathematical method of finding a surface that focuses a finite size source has been developed. We show its use solving two particularly simple cases in which we compare the energy efficiency of the new surface to the classical elliptical cavities. In the examples given, the new designs are frequently advantageous.
authors.forename: R
authors.initials: R
authors.lastname: Weigand
authors.forename: J M
authors.initials: JM
authors.lastname: Guerra