Abstract: An optical element having an optical axis, and comprising a plurality of definable adjacent zones of optical material, each zone having a definable refractive index different from the refractive index of an adjacent zone and an Abbe number, the zones of optical materials being arranged parallel to each other to define a profile of refractive indices which is symmetric about a plane of symmetry along the optical axis of the element and parallel to the zones. In one embodiment the optical element is a spectrally invariant lens.

Abstract: A method of manufacturing an optical device having a profile of refractive indices along its optical axis. A desired volume of each of a plurality of types of optical material are dispensed into a mold of known plan area in the form of a frit or a melt and the mold is heated to cause the materials to melt and fuse together to define a contiguous body of optical material having a desired profile. As the optical materials melt, the different types of material separate out so that they are arranged with the most dense material closest to the bottom of the mold and the least dense material closest to the top of the mold. To enhance this effect, the optical materials are layered in the mold in decreasing order of density of the materials from the bottom to the top so that the layers of optical material with the greater densities are closer to the bottom of the mold than the layers of materials with lesser densities.

Abstract: A lens element (40) is formed from a monolithic unit (46) having two sections (46A and 46B) aligned on an optical axis. A selected one of the sections has an axial gradient refractive index, and the other has a homogeneous refractive index. A first surface 42 is generated one section and a second surface is generated on the other. The axial gradient index material may be selected such that third order spherical aberration of the element is zero. The axial gradient index material may be selected such that similarly constructed elements having shape factors between about 0 and 2.0 also have zero third order spherical aberration. Another element (20) may be formed entirely from an axially graded refractive index material. The refractive index preferably varies as a non-linear function of at least distance along the optical axis. The refractive index function and index change may be selected such that a selected third order aberration is zero or some constant value over a wide range of shape factor.

Abstract: A fused glass block having an axial gradient index of refraction profile between two opposed parallel surfaces, with a change in refractive index from one of the surfaces to the other ranging from about 0.04 to 0.47, is provided. The fused glass block has a change in thermal expansion coefficient from one of the surfaces to the other of less than about 3.times.10.sup.-7 .degree.C..sup.-1, has essentially no strain or birefringence therein, and has a smoothly varying refractive index profile from one of the surfaces to the other. The fused glass block is prepared from at least two pre-selected compositions of a lead-silicate glass series that has been discovered to provide the requisite properties.

Abstract: Shaped gradient profiles of index of refraction in lenses are fabricated from axial gradients. While the resulting lens has both radial (or cylindrical) and axial components, and, strictly speaking, is not a pure radial (cylindrical) gradient, nonetheless, the presence of both the radial and axial components or cylindrical and axial components provides lens designers with greater flexibility in lens design than heretofore existed.

Abstract: Tailored glass bodies (10) having a substantial change in index of refraction (a .DELTA.n of at least about 0.08 along an axis) are provided. The glass body is characterized by two substantially parallel surfaces, with one surface having a first composition (12t) and the other surface a second composition (12b). The composition of the glass body varies in some predetermined fashion between the two surfaces (12i1-12i8) to provide a predetermined graded index of refraction. A method is also provided to tailor the glass body so that the two compositions have one or more of the following properties substantially constant: thermal coefficient of expansion, glass fusion temperature, Abbe value, and density.