Differential equations for design of a freeform single lens with prescribed irradiance properties

Abstract. The design equations of a freeform single lens optical systems for redistributing the input radiation in a prescribed manner over a given target set are presented in explicit form. These equations are derived here and their analysis is carried out in geometrical optics approximation. The qualitative properties of solutions to such problems are discussed in detail and illustrated by examples. Difficulties arising in numerical computations of solutions in the rotationally symmetric case are also noted.