The NANOMEFOS non-contact measurement machine for freeform optics

Henselmans, R.; Cacace, L.A.; Kramer, George F.; Rosielle, P.C.J.N.; Steinbuch, M Maarten

doi:10.1016/j.precisioneng.2011.04.004

Cited by 94 publications

(63 citation statements)

References 9 publications

(13 reference statements)

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“…err., generated errors. guiding systems [31,33]. The generated PV value of the Fourier harmonics (≈609 nm) corresponds to a realistic form error on aspherical lenses…”

Section: Combined Random and Systematic Errorsmentioning

confidence: 96%

A new method for aspherical surface fitting with large-volume datasets

El-Hayek

Nouira

Anwer

et al. 2014

Precision Engineering

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tIn the framework of form characterization of aspherical surfaces, European National Metrology Institutes (NMIs) have been developing ultra-high precision machines having the ability to measure aspherical lenses with an uncertainty of few tens of nanometers. The fitting of the acquired aspherical datasets onto their corresponding theoretical model should be achieved at the same level of precision. In this article, three fitting algorithms are investigated: the Limited memory-Broyden-Fletcher-Goldfarb-Shanno (L-BFGS), the Levenberg-Marquardt (LM) and one variant of the Iterative Closest Point (ICP). They are assessed based on their capacities to converge relatively fast to achieve a nanometric level of accuracy, to manage a large volume of data and to be robust to the position of the data with respect to the model. Nevertheless, the algorithms are first evaluated on simulated datasets and their performances are studied. The comparison of these algorithms is extended on measured datasets of an aspherical lens. The results validate the newly used method for the fitting of aspherical surfaces and reveal that it is well adapted, faster and less complex than the LM or ICP methods.

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“…err., generated errors. guiding systems [31,33]. The generated PV value of the Fourier harmonics (≈609 nm) corresponds to a realistic form error on aspherical lenses…”

Section: Combined Random and Systematic Errorsmentioning

confidence: 96%

A new method for aspherical surface fitting with large-volume datasets

El-Hayek

Nouira

Anwer

et al. 2014

Precision Engineering

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“…Specifically for freeform measurement we have developed a unique absolute metrology tool called NANOMEFOS that has the capability of noncontact measuring surfaces with an uncertainty better than 15 nm rms [5]. It is fast, universal, and can accommodate large work pieces.…”

Section: B Measurementmentioning

confidence: 99%

The TROPOMI Telescope

Nijkerk

Venrooy

Doorn

et al. 2017

International Conference on Space Optics — ICSO 2012

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Abstract-In this paper, we discuss the two-mirror pushbroom telescope for TROPOMI. Using freeform optics, it has unprecedented resolution. The complete cycle of freeform optical design, analysis, manufacturing, metrology and functional test on a breadboard setup is described, focusing on the specific complexities concerning freeforms. The TROPOMI flight telescope will be manufactured in summer 2012. freeform optics; asphere; metrology; TROPOMI; NANOMEFOS

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“…The asphere was polished from 5µm PV to 24 nm rms in 6 runs. Figure 6 shows the final result as measured with the NANOMEFOS measurement machine [5]. This non-contact measurement machine typically obtains 2k x 2k points in about 15 minutes, giving interferometric resolution with nm level accuracy (Figure 7).…”

Section: L2 Fabricationmentioning

confidence: 99%

Design, analysis, and testing of the optical tube assemblies for the ESO VLT four laser guide star facility

et al. 2012

Self Cite

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TNO has developed the Optical Tube Assemblies (OTAs) for the ESO VLT Four Laser Guide Star Facility. The OTAs are Galilean 20x beam expanders, expanding a ∅15 mm input beam (25W, 589 nm CW) to a steerable ∅300 mm output beam. TNO has recently successfully completed acceptance testing of the four units, showing compliance to the challenging requirements on output wavefront quality, thermally induced defocus under operational conditions, absolute pointing accuracy and polarization extinction ratio (PER).TNO applied its corrective polishing in combination with the NANOMEFOS measurement machine to produce the ∅380 mm aspherical output lens, resulting in 20 nm rms output wavefront quality. The thermal behaviour of the system has been analyzed by combining optical, lumped mass and FE analyses. A design that is passively athermalized over a large temperature range as well as under the influence of thermal gradients has been developed. Extensive thermal testing has shown a thermally induced defocus of less than 0.15 waves under the operational conditions of 0-15°C and upto -0.7°C/hr gradient. A custom tip-tilt mechanism was designed to steer the output beam over a 4.8 arcmin radius, with less than 0.1" (3σ) accuracy at 1 Hz update rate. The PER was also measured under operational (thermal and tilt) conditions and demonstrated to be well above 99%. This paper describes the design, modelling and analysis, and the test results of these instruments.

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The NANOMEFOS non-contact measurement machine for freeform optics

Cited by 94 publications

References 9 publications

A new method for aspherical surface fitting with large-volume datasets

A new method for aspherical surface fitting with large-volume datasets

The TROPOMI Telescope

Design, analysis, and testing of the optical tube assemblies for the ESO VLT four laser guide star facility

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