RESUMEN
A new method for controlling the shape and increasing the maximum index change in the radial gradient-index profile of sol-gel bodies is demonstrated. This is accomplished by modifying the relative rates of the intricate reactions responsible for forming the gradient. In practice the changes reported here are effected solely by varying the leaching conditions. Through the proper choice of a solution to arrest the leaching action, the index change can be maximized for a given shape to double that of the previous technique. A detailed composition analysis of the data reveals that dopant diffusion and precipitation are the dominant factors influencing the observed results.
RESUMEN
This study investigates the role of gradient-index materials in the design of Cooke triplets for use as 35-mm format photographic objectives. Cooke triplet designs are presented with different types of gradient-index profiles. Both linear axial and shallow radial gradients are shown to provide effective control of spherical aberration and astigmatism. In particular, a Cooke triplet with a combination of both linear axial and radial gradients attains performance comparable to a six-element double Gauss lens. In virtually all cases, the use of gradient-index components improves the Cooke triplets' performance significantly.
RESUMEN
Two new techniques for altering the gradient-index profile shape are presented using ion exchange of Li(+) for Na(+) in an aluminosilicate glass. By varying the alkali concentration in the base glass and salt melt, the functional form of the index profile is modified to range in shape from convex to concave. The success of these techniques is attributed to the unusual characteristics of the initial system, which are shown to be caused by a nonlinear dependence of refractive index on dopant concentration.
RESUMEN
Three- and four-element eyepiece designs are presented each with a different type of radial gradient-index distribution. Both quadratic and modified quadratic index profiles are shown to provide effective control of the field aberrations. In particular, the three-element design with a quadratic index profile demonstrates that the inhomogeneous power contribution can make significant contributions to the overall system performance, especially the astigmatism correction. Using gradient-index components has allowed for increased eye relief and field of view making these designs comparable with five- and six-element ones.
