Boundary conditions for balancing light in tailoring freeform surfaces

Tailoring allows designing a freeform optical surface which precisely produces a desired irradiance distribution on a desired target from a known small source by solving a partial differential equation. Existence and uniqueness of the solution depends on the boundary conditions. We present two alternative types of boundary conditions which ensure a unique exact solution. We have implemented and tested these boundary conditions in our freeform tailored optics package ffTOP®.