A stacked array magnifier (SAM) forms a magnified, demagnified or unit image of an object. The SAM includes one or more non-refractive lenslet arrays and one or more refractive lenslet arrays to form a plurality of lenslet channels. Each lenslet channel has at least one refractive lenslet and at least one non-refractive lenslet. SAMs are combined and tiled to form a scaleable display of flat panel displays. Multiple SAMs are used to increase magnification selectively. Hybrid lenslet arrays of the invention are also useable for optical processing and non-imaging applications.

Lenslet array systems and methods

The ReSTOR intraocular lens presents a unique apodized diffractive design within a refractive foldable acrylic optic, which makes an unprecedented level of mulifocal optical performance available. We describe the history and principles of diffractive optics used in the development of this refractive-diffractive IOL.

History and development of the apodized diffractive intraocular lens.

Diffractive lenses have been traditionally designed with the first diffracted order. The spectral characteristics of diffractive lenses operating in higher diffracted orders differ significantly from the first-order case. Multiorder diffractive lenses offer a new degree of freedom in the design of broadband and multispectral optical systems that include diffractive optical elements. It is shown that blazing the surface-relief diffractive lens for higher diffraction orders enables the design of achromatic and apochromatic singlets. The wavelength-dependent optical transfer function and the associated Strehl ratio are derived for multiorder diffractive lenses. Experiments that illustrate lens performance in two spectral bands are described, and the results show excellent agreement with the theoretical predictions.

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Spectral properties of multiorder diffractive lenses

Fabrication of diffractive optics with binary masks requires multiple photolithographic processes to produce high-efficiency elements. Alignment or etching errors at any stage of fabrication decrease the efficiency of the element. We developed an easily accessible procedure that reduces fabrication complexity and costs by using a single gray-scale mask. The gray-scale patterns are generated by commercial slide imagers and are then photoreduced onto low-contrast film plates. Multiple-level or continuous relief structures (kinoforms) may be constructed by use of the photoreduced gray-scale patterns as lithographic masks. Diffractive-optic lenses and blazed gratings were fabricated in photoresist with this procedure. First-order diffraction efficiencies as high as 85% were measured for the blazed gratings. The advantages and the limitations of this technique are discussed.

Gray-scale masks for diffractive-optics fabrication: I. Commercial slide imagers.

A method of designing a multifocal ophthalmic lens with one base focus and at least one additional focus, capable of reducing aberrations of the eye for at least one of the foci after its implantation, comprising the steps of: (i) characterizing at least one corneal surface as a mathematical model; (ii) calculating the resulting aberrations of said corneal surface(s) by employing said mathematical model; (iii) modeling the multifocal ophthalmic lens such that a wavefront arriving from an optical system comprising said lens and said at least one corneal surface obtains reduced aberrations for at least one of the foci. There is also disclosed a method of selecting a multifocal intraocular lens, a method of designing a multifocal ophthalmic lens based on corneal data from a group of patients, and a multifocal ophthalmic lens.

Multifocal ophthalmic lens

The optical properties of holographic kinoforms are described. It is shown that paraxial designs are not adequate for f /Nos. less than ~F/10. A nonparaxial design is introduced that retains the high diffraction efficiency of the paraxial designs, yet also produces an unaberrated diffracted wavefront for the design wavelength. Aberration calculations and computer calculations, based on the Huygens-Fresnel principle, of the point spread functions for these elements show the necessity of using the nonparaxial design. Specifications for a surface profile that takes account of the finite thickness of the diffracting surface are given. A model for kinoforms which can be used in optical design programs is proposed.

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Optical performance of holographic kinoforms

The so-called group index of refraction may be measured by observing the shift of the visibility envelope when a sample is inserted into one arm of a Twyman–Green interferometer. Although the group and phase index curves are related, the phase index cannot be directly calculated from the group index because there are infinitely many phase index curves that correspond to any given group index curve. A method of selecting the correct dispersion curve from the family of possibilities is presented, using a priori information based on common properties of known glasses. This allows the phase index to be calculated from the group index to an accuracy of ~0.0016 across the visible spectrum.

Conversion of group refractive index to phase refractive index

An experimental apparatus has been designed to measure group refractive index (ng) by observing the shift of the fringe visibility envelope upon insertion of a sample into one arm of a Twyman-Green interferometer. A criterion is developed for the limiting bandwidth and thickness for which good visibility may be expected and for predicting the bandwidth for the narrowest visibility curve. It is demonstrated that the measured group index data can be converted to phase index data with a previously described technique [ J. R. Rogers M. D. Hopler , J. Opt. Soc. Am. A5, 1595– 1600 ( 1988)] to an accuracy of ~0.0006 across the visible spectrum.

Interferometric measurement of group and phase refractive index

A simple aberration theory is described for systems containing tilted and decentered surfaces. Design principles are developed and applied to two and three mirror systems.

Vector Aberration Theory And The Design Of Off-Axis Systems

The properties of the Y−Ӯ diagram as applied to radial gradient lens systems are developed. It is shown that the diagram consists of elliptical arcs, which are circular arcs for certain conditions. The effects of pupil and object shifts are discussed as well as the effects of scaling the pupil size. It is shown how the constructional parameters of the system are read from the diagram. Finally, for the purpose of design, it is shown how one may obtain the Y−Ӯ diagram of a system which satisfies a certain set of design constraints.

John R. Rogers

Papers

Optical performance of holographic kinoforms

Conversion of group refractive index to phase refractive index

Interferometric measurement of group and phase refractive index

Vector Aberration Theory And The Design Of Off-Axis Systems

The Y-? diagram for radial gradient systems.