Multifocal spectral diffractive lens

We present a method for calculating a spectral multifocal diffractive lens that forms a given set of fixed-position foci at multiple operating wavelengths. It is based on minimizing a function represented as a squared absolute value of difference between the complex amplitudes of beams formed by the relief of a spectral lens at the given wavelengths and the complex transmission functions of multifocal lenses calculated for these wavelengths. As an example, we calculated zone plates that form three fixed foci at three and four operating wavelengths. The results obtained may find application in the development and creation of new multifocal contact and intraocular lenses with reduced chromatic aberrations.