Topic
Apochromat
About: Apochromat is a research topic. Over the lifetime, 642 publications have been published within this topic receiving 7934 citations.
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TL;DR: Two novel schemes for correction of spherical aberration are proposed and studied and the accuracy of the proposed aberration correction schemes is validated.
Abstract: As with a conventional lens, a Fresnel zone lens (FZL) can be used to image objects at infinity or nearby In the latter case, the FZL converts a diverging spherical wavefront into a converging spherical wavefront The glass substrate on which the FZL is fabricated introduces spherical aberration resulting in a shift of the image plane and blurring of the image Two novel schemes for correction of this spherical aberration are proposed and studied in this paper To demonstrate them, FZLs are designed with and without aberration correction They are fabricated using electron beam direct writing The devices are evaluated and the accuracy of the proposed aberration correction schemes is validated
18 citations
Patent•
18 Jul 1989TL;DR: In this article, a lens triplet consisting of two identical aspherical acrylic lens elements and a liquid lens element is well-corrected for chromatic aberration and for spherochromatism, and is diffraction limited over the visible spectrum.
Abstract: A lens triplet consisting of two identical aspherical acrylic lens elements and a liquid lens element is well-corrected for chromatic aberration and for spherochromatism, and is diffraction limited over the visible spectrum. The liquid lens element is made of an optical liquid selected because of its compatibility with acrylic for achieving paraxial color correction with negligible chromatic variation of spherical aberration. One surface of each acrylic lens element is aspherized to minimize spherical aberration.
18 citations
TL;DR: Design and performance of laboratory prototype for a compact near infrared acousto-optic imaging spectro-polarimeter, which may be implemented for remote or close-up analysis of planetary surfaces and is considered as a potential reconnaissance and analysis tool for future planetary or moon landers and rovers.
Abstract: Spectral imaging in the near infrared is a promising method for mineralogy analysis, in particular well-suited for airless celestial objects or those with faint atmospheres. Additional information about structure and composition of minerals can be obtained using spectral polarimetry with high spatial resolution. We report design and performance of laboratory prototype for a compact near infrared acousto-optic imaging spectro-polarimeter, which may be implemented for remote or close-up analysis of planetary surfaces. The prototype features telecentric optics, apochromatic design over the bandwidth of 0.8–1.75 µm, and simultaneous imaging of two orthogonal linear polarizations of the same scene with a single FPA detector. When validating the scheme, reflectance spectra of several minerals were measured with the spectral resolution of 100 cm−1 (10 nm passband at 1 µm). When imaging samples, the spatial resolution of 0.6 mm at the target distance of one meter was reached. It corresponds to 100 by 100 diffraction-limited elements resolved at the focal plane array (FPA) for each of the two light polarizations. A similar prototype is also being designed for the spectral range from 1.7 to 3.5 µm. This type of the spectro-polarimeter is considered as a potential reconnaissance and analysis tool for future planetary or moon landers and rovers.
18 citations
Patent•
17 Apr 1996
TL;DR: In this article, a high-magnification and high-NA objective with a long working distance was proposed for correcting chromatic aberrations over a wide wavelength range and allowing an aligning pupil position without making much use of cemented lenses.
Abstract: The invention provides a high-magnification and high-NA objective having a long working distance, which is corrected for various aberrations, especially chromatic aberrations over a wide wavelength range and allowed to have an aligning pupil position without making much use of cemented lenses and anomalous dispersion glass. The objective comprises a first lens group G1 including a meniscus lens concave on the object side and having a positive power as a whole, two optical elements of the diffraction type (DOEs), and a second lens group G2 including at least one cemented lens, and satisfies the condition for ensuring the edge thickness of the front lens as well as either one of two conditions for making effective correction for longitudinal chromatic aberration and chromatic aberration of magnification.
18 citations
Patent•
10 Jun 1993
TL;DR: In this paper, the authors proposed a lens with at least an aspheric surface in which the radius of curvature becomes larger from an optical axis toward a periphery as one surface, and constituted so that either surface may be a diffraction lens surface formed like stairs as an annular band dispersedly shifting in a direction where lens thickness is increased according as being away from the optical axis.
Abstract: PURPOSE: To provide a lens capable of correcting chromatic aberration without increasing the component number of lenses by utilizing a diffraction effect. CONSTITUTION: This lens has at least an aspheric surface in which the radius of curvature becomes larger from an optical axis toward a periphery as one surface, and it is constituted so that at least either surface may be a diffraction lens surface formed like stairs as an annular band dispersedly shifting in a direction where lens thickness is increased according as being away from the optical axis. COPYRIGHT: (C)1994,JPO&Japio
17 citations