Kevin P. Thompson and Jannick P. Rolland reported on the freeform revolution in the paper, ‘Freeform Optical Surfaces: A Revolution in Imaging Optical Design,’ in Optics and Photonics News, Vol. 23, Issue 6, pp. 30-35 (2012)
Abstract: A revolutionary optical surface is the result of developments in the theory of aberrations, techniques in optical system optimization, computation speed, precision fabrication of surfaces without symmetry, and extensions to the range of the surface slopes allowed in optical testing.
2012