Hybrid Objectives Using Gradient-Index Lenses

doi:10.1117/3.2570044.ch9

Book: Optics of Diffractive and Gradient-Index Elements and Systems

Author(s): Grigoriy I. Greisukh, Sergei T. Bobrov, Sergei A. Stepanov

Published: 1997

https://doi.org/10.1117/3.2570044.ch9

Author Affiliations +

Abstract

In the preface to Chap. 8 the advantages and methods of designing homogeneous hybrid objectives were justified. The central ideas outlined there remain in force also for systems with GRIN elements. The simplest inhomogeneous system is a doublet consisting of a powerful GRIN lens and an optically weak corrector. The type of corrector is defined primarily by the aberrations of a GRIN lens it is to correct. To take an example, if a GRIN lens suffers from irremovable field curvature, a homogeneous Smith lens can be used as the corrector. If the spherical aberration is irremovable, a diffractive aspheric can be employed to correct it. Methods of designing simple hybrid systems with correctors of one type or another and the analysis of the capabilities of such systems to form a monochromatic image with high resolution over a wide field are presented in Sects. 9.1 and 9.2. As for chromatic aberrations of hybrid systems, they are not considered for the following reasons. The method of calculating axial and lateral color of hybrid systems is described at length in Chap. 5 and its application to a particular design is not troublesome. The development of special techniques of color correction requires profound and comprehensive investigations into the dispersion properties of graded-index materials.