A new approach to the design of hybrid lenses for integrated optics

The Fresnel lens is one of the most extensively studied components in both classical and integrated optics. This structure is free from axial spherica l aberration, but is heavily affected by both off-axis and chromatic aberra tions. The latter can be compensated by introducing a refractive component, whose chromatic behavior is the opposite of that of the di diffractive len s. This hybrid refractive-diffractive structure, however, is not able to de al effectively with oft-axis aberrations, namely, with coma. In this work, a novel methodology for the design of corrected hybrid lenses is proposed w hich allows for correction of both chromatism and coma. The design: method is based on a ray-optics variational approach which provides a range of pos sible achromatic solutions. An optimization procedure is performed by means of a series of beam propagation method numerical calculations which make i t possible to simulate the lens operation and thus to find the best solutio n.