Iterative wavefront tailoring to simplify freeform optical design for prescribed irradiance

The direct formulation of a freeform optical surface for producing a prescribed irradiance from a point source is very complicated. Instead of directly determining the freeform optical surfaces, we derive a general equation of a parameterized outgoing wavefront, regardless of the structure of the optical element. A separate process is employed to construct the freeform optics following the solution of the wavefront equation. We iteratively revise the wavefront and accordingly update the freeform optics to improve performance. The new method combines two features: (i) the formula derivation process is simplified, and (ii) it could flexibly generate a variety of freeform optical structures with high accuracy.