Design method for color-corrected layered spherical lenses

We consider the problem of designing imaging lenses consisting of thin, concentric, spherical annuli, each having a constant refractive index at a specified wavelength. For single-wavelength designs, we describe a recursive algorithm capable of generating the annular layer structure required to achieve arbitrarily low aberration levels, based on a specified structure of the outer layers. For the design of color-corrected lenses, we show how the single-wavelength design method can provide a parsimonious parametrization scheme that can be used in conjunction with a global optimization process to search for designs exhibiting minimal aberrations over the desired waveband of operation and that also satisfy design constraints.