General stigmatic surfaces.

Given an arbitrary input wavefront, we derive the analytical refractive surface that refracts the wavefront into a single image point. The derivation of the surface is fully analytical without paraxial or numerical approximations. We evaluate the performance of the surface with several cases, and the results were as expected.

General mirror formula for adaptive optics.

We present the general formula to design a mirror such that it reflects the light of a given arbitrary wavefront as a plane wave for two and three dimensions. The formula is fully analytical and close-form. We test the mentioned equations with ray tracing techniques.

Uniqueness of stigmatic solutions.

We compare two analytical methods for designing stigmatic lenses that are based on very different paradigms published recently [Appl. Opt.57, 9341 (2018)APOPAI0003-693510.

General formula to design a freeform singlet free of spherical aberration and astigmatism: reply.

The comment made by Valencia-Estrada and García-Márquez [Appl. Opt.59, 3422 (2020)APOPAI0003-693510.

General formula to design a freeform singlet free of spherical aberration and astigmatism.

In this paper, an analytical closed-form formula for the design of freeform lenses free of spherical aberration and astigmatism is presented. Given the equation of the freeform input surface, the formula gives the equation of the second surface to correct the spherical aberration. The derivation is based on the formal application of the variational Fermat principle under the standard geometrical optics approximation.

General formula for bi-aspheric singlet lens design free of spherical aberration.

In this paper, we present a rigorous analytical solution for the bi-aspheric singlet lens design problem. The input of the general formula presented here is the first surface of the singlet lens; this surface must be continuous and such that the rays inside the lens do not cross each other. The output is the correcting second surface of the singlet; the second surface is such that the singlet is free of spherical aberration.