Second-order supporting quadric method for designing freeform refracting surfaces generating prescribed irradiance distributions

TL;DR

This paper introduces a second-order supporting quadric method for designing freeform refracting surfaces that generate specific irradiance patterns, improving efficiency through second-order optimization techniques.

Contribution

The paper develops a second-order supporting quadric method that simplifies the calculation of quadric parameters for designing optical surfaces, enhancing computational efficiency.

Findings

Efficient design of complex irradiance-generating surfaces

Analytical second derivatives enable second-order optimization

Applicable to non-quadratic cost functions in nonimaging optics

Abstract

We consider the inverse problem of calculating a refracting surface that generates a prescribed irradiance distribution in the far field for a collimated incident beam. This problem can be formulated as a mass transportation problem (MTP) with a quadratic cost function. To solve this problem, we propose a version of the supporting quadric method (SQM), in which the calculation of the quadric parameters is reduced to the problem of minimizing a convex function. We obtain simple analytical expressions for the second derivatives of this function, making it possible to calculate the quadric parameters using second-order optimization methods. This allows us to refer to the proposed method as the second-order SQM. We demonstrate high efficiency of this approach by designing several optical surfaces that generate complex irradiance distributions. We also consider the application of the second-order SQM to nonimaging optics problems described by MTPs with a non-quadratic cost function.