title: Limitations of the ray mapping approach in freeform optics design.
abstract: It was previously demonstrated by Bäuerle et al. [Opt. Express20, 14477 (2012)] that the computation of ray paths through the optical system (ray mapping) can be used to design multisurface freeform optical elements creating a prescribed irradiance pattern for a zero-étendue source. The procedure outlined there uses the heuristic step of reducing the ray mapping's curl to improve adherence to surface integrability criteria. This Letter formally derives a quantitative estimate for the limitations of this approach in the collimated case and shows the key factors influencing the quality of the final optics.
authors.affiliation: RWTH Aachen University, Aachen 52056, Germany.
authors.forename: Adrien
authors.initials: A
authors.lastname: Bruneton
authors.forename: Axel
authors.initials: A
authors.lastname: Bäuerle
authors.forename: Rolf
authors.initials: R
authors.lastname: Wester
authors.forename: Jochen
authors.initials: J
authors.lastname: Stollenwerk
authors.forename: Peter
authors.initials: P
authors.lastname: Loosen