Optische Instrumente und Systeme

Haferkorn, Heinz

doi:10.1007/978-3-322-96431-1_4

Cited by 2 publications

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“…These image distances were calculated for the short reference wavelength (λ F = 486.13 nm) and for the long reference wavelength (λ C = 656.27 nm) of the optical system at an object distance of infinity [15]. In addition, the calculations in Formulas ( 4) and ( 5) use the total focal length of the system f F , f C and the focal length of the first lens f 1F , f 1C at the corresponding wavelength.…”

Section: Paraxial Consideration Of the Equivalent Abbe Number For The...mentioning

confidence: 99%

Extreme Refractive-, Diffractive- and Hybrid-Hyperchromats: Minimizing the Equivalent Abbe Number of a Two-Lens System

et al. 2023

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This work provides a comprehensive analysis of the maximum chromatic axial split of two-element hyperchromats, with the distance between the two lenses being a key variable. Purely refractive and diffractive systems are considered, as well as hybrid layoutscombining refractive and diffractive elements. In order to achieve extreme chromatic axial splitting and accordingly a minimum equivalent Abbe number for lens combinations, a three-step procedure was used. In the first paraxial step, purely optical quantities such as focal lengths of the lenses, inter-lens distances and dispersion properties of the lenses were investigated. In the second step, which also takes place in the paraxial domain, additional geometric boundary conditions such as the radii, diameters and thicknesses of the lenses are taken into account. The results of this step serve as an input for the final optimization using optical design software, which derives practical solutions for minimum equivalent Abbe numbers with diffraction-limited image quality. As a significant result, the comparison with directly cemented lens doublets shows that the introduction of a distance between the elements allows for a much stronger chromatic decomposition for refractive, diffractive and also hybrid combinations. Quantitatively, the minimum equivalent Abbe number for refractive systems is reduced from 2.5 (without spacing) to 1.79 (with spacing). For hybrid combinations, a corresponding reduction from 0.4 to 0.29 is achieved.

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Section: Paraxial Consideration Of the Equivalent Abbe Number For The...mentioning

confidence: 99%

Extreme Refractive-, Diffractive- and Hybrid-Hyperchromats: Minimizing the Equivalent Abbe Number of a Two-Lens System

et al. 2023

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“…As Abbé proposed, the light of the first diffraction order has to pass the aperture of an optical system for proper imaging of an object. 32 Therefore, the angle of the first diffraction maximum has to be less than the aperture angle ␣ of the optics, which is determined by the focal length l of the eye and the entrance pupil of the ophthalmoscope: sin ␣ϭ r l .…”

Section: Spectral and Local Resolutionmentioning

confidence: 99%

Imaging spectroscopy of the human ocular fundus in vivo

Hammer¹

1997

J. Biomed. Opt.

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Spectroscopic measurement of light that is reflected from biological tissue in vivo is being investigated for various clinical applications. One special object of investigation using optical methods is the human ocular fundus. A fundus reflectometer that enables the simultaneous acquisition of up to 192 spectra arranged in a horizontal line across the fundus is described. The underlying optical principle of the device is the confocal imaging of an illuminated narrow, slitlike field at the fundus to the entrance slit of a spectrograph. This is imaged by the grating of the spectrograph onto a two-dimensional CCD chip that records the local distribution of ocular fundus reflectance spectra within a wavelength range of 400 up to 710 nm with a resolution better than 2 nm and a local resolution of 23 m in a field dimension of 1.5 mm. The performance of the device was investigated, the effects of confocal and nonconfocal imaging are discussed, and some representative measurements are presented.

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Optische Instrumente und Systeme

Cited by 2 publications

References 0 publications

Extreme Refractive-, Diffractive- and Hybrid-Hyperchromats: Minimizing the Equivalent Abbe Number of a Two-Lens System

Extreme Refractive-, Diffractive- and Hybrid-Hyperchromats: Minimizing the Equivalent Abbe Number of a Two-Lens System

Imaging spectroscopy of the human ocular fundus in vivo

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