title: Obtaining new local minima in lens design by constructing saddle points.
abstract: We show that in the lens design landscape saddle points exist that are closely related to local minima of simpler problems. On the basis of this new theoretical insight we develop a systematic and efficient saddle-point method that uses a-priori knowledge for obtaining new local minima. In contrast with earlier saddle-point methods, the present method can create both positive and negative lenses. As an example, by successively using the method a good-quality local minimum is obtained from a poor-quality one. The method could also be applicable in other global optimization problems that satisfy the requirements discussed in this paper.
authors.forename: Maarten
authors.initials: M
authors.lastname: van Turnhout
authors.forename: Pascal
authors.initials: P
authors.lastname: van Grol
authors.forename: Florian
authors.initials: F
authors.lastname: Bociort
authors.forename: H Paul
authors.initials: HP
authors.lastname: Urbach