Implementation of FORMIDABLE: a generalized differential optical design library with NURBS capabilities

In this article we describe the implementation of FORMIDABLE: an optical design library capable of simulating optical systems by ray-tracing. Optical performance can be quantified and optimised using third-party optimisation algorithms. Compared to available commercial optical design software and similarly to FANO, our code can simulate and optimise non-uniform rational B-splines surfaces. It also implements generalized differential capabilities that allows faster convergence compared to state-of-the-art. The implementation of FORMIDABLE and its innovative capabilities are described and illustrated with a representative case-study. The source code is available to eligible third-parties under the ECSL licence.