Apochromat

About: Apochromat is a research topic. Over the lifetime, 642 publications have been published within this topic receiving 7934 citations.

Peripheral aberrations in the human eye for different wavelengths: off-axis chromatic aberration

Abstract: The interest in the eye's off-axis aberrations has increased strongly. On-axis the conversion of the aberration magnitude between different wavelengths is well known. We verified if this compensati ...

Progressive multifocal ophthalmic lenses with prism for correcting chromatic aberration

Abstract: A progressive multifocal ophthalmic lens. The lens includes a lens surface having a far vision viewing, a near vision viewing zone and an intermediate vision viewing zone disposed therebetween. A prism having a base is added to the lens. The base lies in the direction of 90° to the lens surface. The prism is added in order to improve chromatic aberration and not to remedy squint.

Chromatic compensation of programmable Fresnel lenses

Abstract: Two proposals to compensate chromatic aberration of a programmable phase Fresnel lens displayed on a liquid crystal device and working under polychromatic illumination are presented. They are based on multiplexing a set of lenses, designed with a common focal length for different wavelengths, and a multicolor filter that makes each sublens work almost monochromatically. One proposal uses spatial multiplexing with mosaic aperture. The other uses a rotating scheme, a color filter against an array of lens sectors, and hybrid spatial-time integration. The central order focalization has a unique location at the focal plane. We have drastically reduced the transversal chromatic aberration of the polychromatic point spread function by properly adjusting the pupil size of each sublens. Depth of focus curves have been made coincident too for the selected wavelengths.

Apochromatic lenses for near-infrared astronomical instruments

Abstract: A method based on the Herzberger approach has been in- vestigated for the selection of glasses for the apochromatic correction at near-infrared (NIR) wavelength. The method avoids the algebraic com- plexity and simplifies the glass selection processes. Doublet and triplet glass combinations can be chosen directly from the plot of partial disper- sion versus V number. Good combinations of NIR doublets and triplets are given. Design examples show that the method is practical and effi- cient. © 1999 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(99)02103-0)

Dispersion and longitudinal chromatic aberration of the crystalline lens of the African cichlid fish Haplochromis burtoni

Abstract: Dispersion and longitudinal chromatic aberration (LCA) of the crystalline lens of the African cichlid fish Haplochromis burtoni were measured with laser lights of four wavelengths: 457, 488, 515, and 633 nm. LCA and spherical aberration, as an indicator of image quality, were determined from the back vertex distances of laser beams deflected by the lens. In the green range between 488 and 515 nm, dispersion is almost constant in the entire lens. In the blue and the red ranges (457–488 and 515–633 nm, respectively), dispersion of lens material increases approximately linearly with increasing refractive index from the periphery to the center of the lens. Spherical aberration and thus monochromatic image quality are independent of the wavelength of light. Dispersion and LCA of the lens are lower than expected from the dispersive properties of ocular media measured in other vertebrate species. Since the lens in fish sets the limit on optical performance, reduction of chromatic aberration of the crystalline lens improves the image quality of the eye.