Hybrid triplet objective with optimum aberration correction

This paper is devoted to the design of a hybrid triplet objective consisting of two refractive lenses and a diffractive element analogous to holographic lens. The possibilities of correcting field aberrations are discussed.Several exemplary solutions of achromatic, apochromatic and quasi-superachromatic hybrid objectives with corrected average field curvature or astigmatism are presented. In the best designs coma is also substantially minimized.