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Apochromat

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


Papers
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Proceedings ArticleDOI
17 Sep 2002
TL;DR: In this article, a microobjective whose optical aberration is carefully corrected can be apochromatic to D, F and C in medium numerical aperture and can be used as objective lens of the optical disk of multi-wavelength, multi-layer and multi-level optical storage.
Abstract: With the increasing demand of huge volume, high density and high transmission speed in optical storage, researches on multi-layer storage and multi-wavelength, multi-layer and multi-level storage in a single substrate have started both in China and abroad. This requests new feathers in optical system of optical disks. The objective lens in multi-layer storage needs compensations to varied spherical aberrations produced by varied thickness of storage layers; the objective lens in multi-wavelength and multi-layer storage needs apochromatism to broadband range. If the apochromatism is not ideal, it is needed that the spherical aberrations of multi-wavelength light are uniform and the multi-wavelength light beams are focused separately to obtain better result. A traditional micro-objective whose optical aberration is carefully corrected can be apochromatic to D, F and C in medium numerical aperture and can be used as objective lens of the optical disk of multi-wavelength, multi-layer and multi-level optical storage. This article gives an amended result based on C. G. Wyne's field flattener. The calculation result of optical aberration indicates that the spherical aberration is nearly zero and the secondary spectrum is less than 0.5 times of focal depth. It is also indicated that the MTF of a certain wavelength light matches the ideal MTF curve wherever on axis or off axis, wherever on meridian surface or on sagittal surface.

1 citations

Proceedings ArticleDOI
F. Yamagishi1, Masayuki Kato1, Satoshi Maeda1, Hiroyuki Ikeda1, T. Inagaki1 
27 Jan 1989
TL;DR: In this article, the authors developed a high numerical aperture grating-lens pair with large wavelength allowance, in which all rays cross the optical axis between the two grating lenses.
Abstract: We have developed a high numerical aperture grating-lens pair with large wavelength allowance. It has a new "center cross" structure, in which all rays cross the optical axis between the two grating lenses. Grating-lenses have concentric grating rings with radii set to cancel the diffraction angle changes caused by wavelength change. Wavelength allowance was estimated using RMS of wavefront aberration. An example calculation showed a wavelength allowance of 20 nm for a numerical aperture of 0.7. This value is sufficient for use with laser diodes with mode hopping or multimode.

1 citations

Patent
21 Mar 2012
TL;DR: In this article, the utility model discloses a 100x flat field apochromatic metallographic microscope objective without CaF2, which is characterized in that the microscope objective is composed of eight lenses which are arranged coaxially and divided into three optical groups.
Abstract: The utility model discloses a100x Flat field apochromatic metallographic microscope objective without CaF2. The microscope objective comprises lenses and is characterized in that the microscope objective is composed of eight lenses which are arranged coaxially and divided into three optical groups, the lenses are a first convex lens, a first concave lens, a second concave lens, a second convex lens, a third concave lens, a third convex lens, a fourth convex lens and a thick aplanatic meniscus lens which are connected in sequence and do not contain CaF2. Compared with similar domestic and oversea lenses, the microscope objective has the advantages of smaller number of lenses, simpler structure and fitting and adjusting technology, lower cost, high cost performance and the like, besides, the microscope objective provided by the utility model does not contain the CaF2, all performance indexes of the microscope objective are better than the existing similar microscope objectives containing the CaF2 and made of TF3 special glass, so that the microscope objective has broad application prospect and good commercial value.

1 citations

Patent
28 Dec 1989
TL;DR: In this article, a double-focus detector utilizing chromatic aberration has been proposed, in which a first object such as a mask is illuminated with a ray of wavelength below 500 nm and a second object such a wafer was illuminated with plural wavelength rays or a wavelength-band ray above 500 nm.
Abstract: A double-focus detector utilizing chromatic aberration has a lens system having axial chromatic aberration in which a first object such as a mask is illuminated with a ray of wavelength below 500 nm and a second object such as a wafer is illuminated with plural wavelength rays or a wavelength-band ray above 500 nm, by employing an image forming plane of the first object with respect to the single wavelength ray as one focal plane of the lens system and the same image forming plane of the second object with respect to the plural wavelength rays or the wavelength-band ray as the other focal plane of the lens system

1 citations


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