Far-Field Reflector Problem Under Design Constraints

The far-field reflector problem is a well-known inverse problem arising in geometric optics. It consists in creating a mirror that reflects a given point light source to a prescribed target light at infinity. In this article, we study this problem under the common design constraint that the mirror is convex and is the graph of a polynomial over a given plane. We propose a method that iteratively improves the optical properties of the mirror surface while strictly fulfilling the design constraints. At each iteration, we first create an initial reflector by solving an optimal transport problem on the sphere. We then parameterize this reflector by the graph of a function over the plane. We test our algorithm with classical target lights at infinity and also show that our approach allows to create reflectors with more complex target lights.