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Topic

Apochromat

About: Apochromat is a(n) research topic. Over the lifetime, 642 publication(s) have been published within this topic receiving 7934 citation(s).


Papers
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Journal ArticleDOI
TL;DR: The reduced eye was further modified by changing the refracting surface to an aspherical shape to reduce the amount of spherical aberration, providing an improved account of both the longitudinal and transverse forms of ocular chromatic aberration.
Abstract: New measurements of the chromatic difference of focus of the human eye were obtained with a two-color, vernier-alignment technique. The results were used to redefine the variation of refractive index of the reduced eye over the visible spectrum. The reduced eye was further modified by changing the refracting surface to an aspherical shape to reduce the amount of spherical aberration. The resulting chromatic-eye model provides an improved account of both the longitudinal and transverse forms of ocular chromatic aberration.

283 citations

Journal ArticleDOI
TL;DR: Hybrid elements containing optical power with both diffractive (holographic) and refractive components are shown to be useful for obtaining arbitrary or, in special cases, achromatic dispersive characteristics.
Abstract: Hybrid elements containing optical power with both diffractive (holographic) and refractive components are shown to be useful for obtaining arbitrary or, in special cases, achromatic dispersive characteristics. In one configuration a volume holographic element is coated on the surface of a crown glass lens, and by varying the power distributions among the refractive and holographic components while maintaining constant overall optical power the effective Abbe V numbers of the resultant hybrid element are shown to span all real numbers excepting a narrow interval around zero. In the achromat case (V number = ∞), both refractive and diffractive components are of the same sign resulting in much smaller glass curvatures than in all-refractive achromat doublets or apochromat triplets. The large separation between holographic partial dispersions and available glass partial dispersions is shown to lead to hybrid three-color achromats with greatly reduced glass curvatures. Applications are expected to include broadband achromatic objectives and chromatic aberration corrector plates in high performance optical systems. Such corrector plates may have any net power (including zero) while exhibiting effective V numbers that are positive or negative and that span a wide range, e.g., ±1 or ±1000. Further advantages include reducing the need for choosing high dispersion glasses, which may be costly and difficult to grind or polish. High diffraction efficiency and broad spectral bandwidths (in excess of 3000 A) are obtained in the holographic optical elements using single-element central-stop and cascaded element designs.

268 citations

Journal ArticleDOI
TL;DR: It is shown that blazing the surface-relief diffractive lens for higher diffraction orders enables the design of achromatic and apochromatic singlets and the wavelength-dependent optical transfer function and the associated Strehl ratio are derived for multiorder diffractive lenses.
Abstract: 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.

238 citations

Journal ArticleDOI
TL;DR: The spherical aberration of the eye was measured by placing a series of centered annular apertures over the eye pupil, and determining the optimum spectacle correction for each aperture by using a “double star” as a test object.
Abstract: The spherical aberration of the eye was measured by placing a series of centered annular apertures over the eye pupil, and determining the optimum spectacle correction for each aperture. A “double star” was used as a test object. Accommodation was controlled by reflecting a second test object into the field of view. The three eyes examined had positive (undercorrected) spherical aberration when unaccommodated; in one case 2 diopters at the pupil margin. The aberration was reduced with increasing accommodation and in one case became negative at high accommodation. Homatropine reduced the spherical aberration of two of the three eyes examined. A historical review of previous work is given.

141 citations

Patent
28 Feb 2011
Abstract: The subject invention provides lenses, and methods for designing and manufacturing these lenses, with reduced chromatic aberration. Advantageously, these lenses are specifically designed to correct chromatic aberration that results as multichromatic light passes through the lenses.

137 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20214
20204
20196
20188
201716
201625