Showing papers on "Apochromat published in 2009"

Lens optical properties in the eyes of large marine predatory teleosts.

Abstract: The optical properties of the crystalline lenses were studied in a variety of large predatory teleosts (bony fishes) that forage in the open ocean, some of them at considerable depths. We found the first fish lenses that are free of measurable longitudinal spherical aberration, i.e., are perfectly monofocal, in contrast to the multifocal lenses that are typical for smaller fishes living close to the surface. In fact, none of the lenses investigated in this study were clearly multifocal. Most, but not all, of the lenses had long normalized focal lengths (focal length/lens radius) of up to 3.3 lens radii. A monofocal lens of long focal length, combined with spectrally suitably placed cone pigments, may be the optimal solution for vision of high spatial and spectral resolutions in a habitat where the available spectrum of light is limited.

Aberration effects on femtosecond pulses generated by nonideal achromatic doublets

Abstract: There are three main effects that affect the femtosecond pulse focusing process near the focal plane of a refractive lens: the group velocity dispersion (GVD), the propagation time difference (PTD), and the aberrations of the lens In this paper we study in detail these effects generated by nonideal achromatic doublets based on a Fourier-optical analysis and Seidel aberration theory considering lens material, wavelength range, lens surface design, and temporally and spatially uniform and Gaussian intensity distributions We show that the residual chromatic aberration in achromatic lenses, which has been neglected so far, has a considerable effect on the focusing of pulses shorter than 20 fs in the spectral range between the UV and IR, 300 to 1100 nm, and is particularly important in the blue and UV spectral range We present a general fitted function for an estimation of the pulse stretching parameter, which depends only on the numerical aperture and focal length of the doublet as well as the wavelength of the carrier of the pulse

Chromatic aberrations of diffractive-refractive intraocular lenses in an eye model

Abstract: Results of analyzing chromatic aberrations of an eye model with different designs of intraocular lenses (IOLs), that is, artificial crystalline lenses (refractive, diffractive-refractive, diffractive, and harmonic, i.e., multiorder lenses) are represented. Investigations were carried out sequentially for elements of the model, namely, for a cornea, refractive and diffractive components, and IOL, and as a whole, for a cornea + IOL. It is shown that diffractive-refractive IOLs in which the diffractive components produce a positive additional focal power possess the best chromatic characteristics. Chromatic aberration of the eye model with such IOLs is 2 times less than that of a model with a refractive IOL, whereas with other IOL designs it is 2 times greater and even more.

Functional characterization of a liquid lens using a Zygo interferometer

Abstract: In this study, the opto-mechanical design and functional characterization of a Variable Focal Liquid Length Lens (VFLLL) are presented. This VFLLL is formed by a hydro-pneumatic system, a mount with two elastic membranes and the liquid medium between them. The hydropneumatic system allows the entrance and exit of the liquid at any moment to change the shape of the surfaces as well as the axial thickness of the lens. The functional characterization consists in measure the spherical aberrations present in VFLLL when changes on the amount of liquid medium are made. We used the Zygo interferometer to measure the spherical aberration. The changes of aberration as function of the focal length are shown. Finally the experimental results are presented.

Progressive chromatic aberration corrected ocular lens

Abstract: A method to reduce ocular chromatic aberrations using a lens or other spatial structure to selectively band-pass filter transmitted light of certain wavelengths. The ocular lens overcomes the negative effects of the wavelength band pass filter lenses while maintaining its ability to reduce the negative effects of chromatic aberration. The band-pass filter is applied in one or more concentric zones and or angular regions. The lens power is adjusted in concert with the band-pass filter wavelength to minimize aberrations. Variations include the application of the band-pass filter being applied to an angular region and no filter is applied to another. Alternatively the band-pass filter is not applied to one or more concentric ring regions and is applied to one or more angular regions. The band-pass filter can be applied to the surface of the lens or spatial structure, or applied to the lens material.

Aberration correction apparatus that corrects spherical aberration of charged particle apparatus

Abstract: To provide an aberration correction configuration that can realize both an aberration correction function for a long focus and an aberration correction function for a short focus. While having a conventional aberration correction apparatus configuration that has two rotationally symmetric lenses arranged between two multiple lenses, three rotationally symmetric lenses are disposed between an objective lens and a multiple lens instead of the conventional arrangement in which two rotationally symmetric lenses are disposed therebetween. When using the objective lens with a long focal length, aberrations are corrected using two rotationally symmetric lenses among three rotationally symmetric lenses disposed between the objective lens and the multiple lens. When using the objective lens with a short focal length, e.g. for high resolution observation, aberrations are corrected using two rotationally symmetric lenses of a different combination to those used for a long focus, among the three rotationally symmetric lenses disposed between the objective lens and the multiple lens.

Optical design of apochromatic objective of wide spectral and long focal

Abstract: The design method of a refracting telephoto objective with wide spectral and long focal is introduced.Suitable glass materials for correction of secondary spectrum are analyzed,and the system of apochromatic equations for solving the range of each lens power in the triplet lens is established.A design example of a lens whose operating wavelength is 0.4～0.9μm,focal length is 400 mm,full field-of-view angle is 6.2° and relative aperture is 1:4 is given on the basis of the theoretical calculation and the optimization of optical design software ZEMAX.The result of design shows that aberration of secondary spectrum is well corrected and image quality is good.

Apochromatic object lens

Abstract: PROBLEM TO BE SOLVED: To provide an apochromatic object lens to which apochromatic correction is performed over a wide wavelength region, which hardly has distortion aberration even with a very large image area to be formed. SOLUTION: This apochromatic object lens includes diaphragms 4 and a plurality of optical members each of which is a refractive optical member. The optical members constitute a plurality of lens groups 1, 2, 3 and include a plurality of lenses L1, L2, L3, L4, L5, L6, L7, L8 arranged on one optical axis (X). As for the forming material of the lenses, a plurality of different kinds of materials are used. Each of the lenses L1, L2, L3, L4, L5, L6, L7, L8 is formed of any of calcium fluoride CaF2, synthetic quartz SiO2, or the other radiation resistance optical material SR. COPYRIGHT: (C)2010,JPO&INPIT