Self-weight distortion of lens elements

DeWitt, Frank A.; Nadorff, Georg; Naradikian, Markar

doi:10.1117/12.679138

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…Here, the position and magnitude of the force were optimized based on elastic shell theory models of large aperture optical components to get the best deformation compensation effect. In addition, Dewitt et al [14] developed equations for describing the gravity-induced deformation of optical lenses, and the effects of lens size, material, and mounting method on the deformation were analyzed. ese methods could be conceivably employed to compensate for the gravity-induced deformation of large aperture reference mirrors employed in interferometer systems used for measuring the surface accuracy of high-precision optical components.…”

Section: Introductionmentioning

confidence: 99%

Multiposition Rotation Interference Absolute Measurement Method for High-Precision Optical Component Surfaces

Zhu

Nie

Liu

et al. 2021

International Journal of Optics

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Modern optical engineering requires increasingly sophisticated interferometry methods capable of conducting subnanometer scale measurements of the large aperture, high-precision optical component surfaces. However, the accuracy of interferometry measurement is limited to the accuracy with which the surface of the reference mirror employed in the interferometer system is known, and the influence of gravity-induced deformation cannot be ignored. This is addressed in the present work by proposing a three-flat testing method based on multiposition rotation interference absolute surface measurement technology that combines the basic theory of N-position rotation with the separability of surface wavefront functions into sums of even and odd functions. These functions provide the rotational symmetric components of the wavefront, which then enables the absolute surface to be reconstructed based on the N-position rotation measurements. In addition, we propose a mechanical clamping combined with computational method to compensate for the gravity-induced deformations of the flats in the multiposition rotation absolute measurements. The high precision of the proposed absolute surface measurement method is demonstrated via simulations. The results of laboratory experiments indicate that the combination compensation method provides the high-precision surface reconstruction outcomes. The present work provides an important contribution for supporting the interferometry measurement of large aperture, high-precision optical component surfaces.

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Section: Introductionmentioning

confidence: 99%

Multiposition Rotation Interference Absolute Measurement Method for High-Precision Optical Component Surfaces

Zhu

Nie

Liu

et al. 2021

International Journal of Optics

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Measurement of the surface form error of large aperture plane optical surfaces with a polarization phase-shifting liquid reference reflection Fizeau interferometer

et al. 2016

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A polarization phase-shifting liquid reference reflection Fizeau interferometer has been proposed. A polarization cyclic path optical configuration along with a concave telescope mirror is used to produce a pair of expanded, collimated p and s polarized beams with a small angular separation between them. The collimated beams are deflected along a vertical direction toward a Fizeau interferometer cavity formed between a liquid surface that acts as a reference surface and a plane test surface. Either the p or s polarized beam is allowed to strike the liquid surface normally and the orientation of the test surface is adjusted to reflect the other beam, having orthogonal linear polarization, in the direction of the normally reflected reference beam from the liquid surface. A combination of a quarter-wave plate and linear polarizer is used to apply polarization phase shift between the test and reference beams, and quantitative surface form error is measured by applying phase-shifting interferometry. A method for elimination of the residual system aberration is discussed. Results obtained for an optically polished BK-7 disk of clear aperture diameter ≈160 mm are presented.

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Equivalent Modeling and Verification of a High-Steepness and Lightweight Elliptical Aluminum Mirror

et al. 2022

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In order to realize the compact layout of aerospace payloads, the design and manufacture of high-steepness lightweight aluminum alloy mirrors is a key technology to be explored. For high-steepness mirrors, the traditional method is to establish the initial thickness that satisfies the bending stiffness through finite element optimization iteration, which cannot achieve fast modeling and performance estimation. In this paper, firstly, the equivalent modeling method of the mirror with high steepness is proposed to achieve the equivalent of the elliptic mirror with a diameter of 410 × 310 mm and F# less than 0.7. Based on the mathematical model, topology shape optimization was used to build a highly lightweight mirror structure that could be quickly assembled, and the equivalent area–mass density of the mirror is less than 34 kg/mm2. Next, the rationality of design feasibility was verified by simulation analysis. Finally, by using single point diamond turning combined with post polishing process, the high-precision manufacturing of conventional aluminum alloy mirror was realized. The results show that the mirror shape accuracy is 1/10 λ (λ = 632.8 nm), and the surface roughness Ra is 3.342 nm. This research provides strong theoretical support and application prospects for the low-cost and rapid manufacturing of high-steepness lightweight aluminum alloy mirrors.

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Self-weight distortion of lens elements

Cited by 3 publications

References 2 publications

Multiposition Rotation Interference Absolute Measurement Method for High-Precision Optical Component Surfaces

Multiposition Rotation Interference Absolute Measurement Method for High-Precision Optical Component Surfaces

Measurement of the surface form error of large aperture plane optical surfaces with a polarization phase-shifting liquid reference reflection Fizeau interferometer

Equivalent Modeling and Verification of a High-Steepness and Lightweight Elliptical Aluminum Mirror

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