Hybrid singlet arbitrarily dispersive element

Hybrid elements containing optical power with both diffractive (holographic) and refractive components are shown to be useful for obtaining arbitrary, or in a special case, achromatic, dispersive characteristics. In one configuration a volume holographic element is coated on the surface of a crown glass lens, and by varying the power distributions among the refractive and holographic components while maintaining constant overall optical power the effective Abbe V numbers of the resultant hybrid element are shown to span all real numbers except a narrow interval around zero.