Until recently, the dimensions of typical optical systems were much greater than optical wavelengths. Specialists in geometrical optics
studied refraction using aberrations and rays, and specialists in physical optics studied images using waves, with neither group having much in common with the other. Now, however, optical wavelengths are not considered as short as
they used to be. At the same time, there is a lack of people competent in both geometrical and
physical optics.We have the tools to tackle challenging and exciting problems of much greater
scope and interest than ever before, but fewer and fewer people know how to use these tools. Nearly twenty years ago, Warren Smith wrote an article entitled “The Vanishing Lens Designer;” today, the dwindling number of expert lens designers has become a problem that is even
more keenly felt.