The design and underlying theory is given for an aspheric singlet lens capable of operating, with minimum sphero-chromatic aberration, over a range of pre-selected wavelengths. The performance of the lens is compared with a conventional aspheric (based on Fermat's principle) using finite ray tracing techniques. The use of the lens as a focusing element in a multi-wavelength high-power laser is evaluated. Finally, comments are made on its manufacture and testing and its performance compared with theoretical prediction.
D. J. Nicholas, D. J. Nicholas,
"The Use Of Perturbed Aspherics In Broad Band Optical Systems", Proc. SPIE 0645, Optical Manufacturing, Testing and Aspheric Optics, (3 November 1986); doi: 10.1117/12.964490; https://doi.org/10.1117/12.964490