Fundamentals of macro axial gradient index optical design and engineering

Homogeneous lens material is characterized by an index of refraction and a point on the glass map n(d) = f(v(d)). Gradient refractive index (GRIN) lenses have a spatially varying index and dispersion and are represented by a line on the glass map. GRIN tenses open the door to a wide variety of optical design applications incorporating entire lenses of axial gradient refractive material (macro-AGRIN). Axial gradient material essentially gives biaspheric behavior to lenses with spherical surfaces and exhibits a controlled gradient in both index and dispersion. Thus, the applications for this material range from simple singlet lens used for imaging laser light, in which spherical aberration is eliminated, to complex multielement lens systems, where improved overall performance is desired. The fusion/diffusion process that produces this material is surprisingly simple, repeatable, and applicable to mass production. The advantages of AGRIN technology coupled with the recent advances in material development and its accessibility in commercially available lens design programs provides optical designers with the opportunity to push the performance of optical systems farther than with conventional optics. (C) 1997 Society of Photo-Optical Instrumentation Engineers.