  We propose a method for designing multifocal diffractive lenses generating
prescribed sets of foci with fixed positions at several different wavelengths.
The method is based on minimizing the difference between the complex amplitudes
of the beams generated by the lens microrelief at the design wavelengths, and
the functions of complex transmission of multifocal lenses calculated for these
wavelengths. As an example, a zone plate generating three fixed foci at three
different wavelengths was designed, fabricated and experimentally investigated.
The proof-of-concept experimental results confirm the formation of foci with
fixed positions at the design wavelengths. The obtained results may find
applications in the design and fabrication of novel multifocal contact and
intraocular lenses with reduced chromatic effects.
