Improving low, mid and high-spatial frequency errors on advanced aspherical and freeform optics with MRF

Maloney, Chris; Lormeau, Jean Pierre; Dumas, Paul

doi:10.1117/12.2236034

Cited by 16 publications

(5 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On top of the dichroic and the M11, we added 5 to 10 nm PVof raster and epicyclic MSF patterns with a 0.74-mm pitch of the grid sag. The amplitude of the MSF aberrations has been tuned to typical manufacturing residuals for high-precision optics 43,45,46 and by checking that the impact on the PSF Strehl and PSF morphology. In parallel, the same aberrations have been projected as atmospheric phase screens at the conjugation altitude (Fig.…”

Section: Simulation Methodologymentioning

confidence: 99%

Performance and limitations of using ELT and MCAO for 50 μas astrometry

Rodeghiero

Arcidiacono

Pott

et al. 2021

J. Astron. Telesc. Instrum. Syst.

View full text Add to dashboard Cite

Multi-conjugated adaptive optics (MCAO) is essential for performing astrometry with the Extremely Large Telescope (ELT). Unlike most of the 8-m class telescopes, the ELT will be a fully adaptive telescope, and a significant portion of the adaptive optics (AO) dynamic range will be depleted by the correction and stabilization of the telescope aberrations and instabilities. MCAO systems are of particular interest for ground-based astrometry since they stabilize the low-order field distortions and transient plate scale instabilities, which originate from the telescope and in the instrument. All instruments have several optical elements relatively far away from the pupil that can potentially challenge the astrometric precision of the observations with their residual mid-spatial frequencies errors. Using a combined simulation of ray tracing and AO numerical codes, we assess the impact of these systematic errors at different field-ofview (FoV) scales and fitting scenarios. The distortions have been assessed at different sky position angles (PA) and indicate that over large FoVs only small PA ranges (AE1 deg to 3 deg) are accessible with astrometric residuals ≤50 μas. A full compliance with the astrometric requirement, at any PA, is achievable for 2 arc sec 2 FoV patches already with a third-order polynomial. The natural partition of the optical system into three segments, i.e., the ELT, the MAORY MCAO module, and the MICADO instrument, resembles a splitting of the astrometric problem into the three subsystems that are characterized by different distortion amplitudes and calibration strategies. The result is a family portrait of the different optical segments with their specifications, dynamic motions, conjugation height, and AO correctability, leading to tracing their role in the bigger puzzle of the 50-μas as astrometric endeavor. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

show abstract

Section: Simulation Methodologymentioning

confidence: 99%

Performance and limitations of using ELT and MCAO for 50 μas astrometry

Rodeghiero

Arcidiacono

Pott

et al. 2021

J. Astron. Telesc. Instrum. Syst.

View full text Add to dashboard Cite

show abstract

“…QED offers a stable, high-performance magnetorheological fluids family, including D10, C10+, D11, C12, and D20, which can meet the polishing requirements of poly-crystalline materials (tungsten carbide and silicon carbide), hardest materials (sapphire), and smoothing of diamond turning marks on infrared optics [ 222 ]. A novel magnetorheological fluid, C30, was designed to reduce defects, increase the laser optics damage threshold, and improve the roughness to 0.1 nm in RMS on a variety of materials, such as SiO 2 [ 223 ], CaF 2 , and Ni [ 224 ].…”

Section: Non-modification Polishing Approachesmentioning

confidence: 99%

Polishing Approaches at Atomic and Close-to-Atomic Scale

2023

View full text Add to dashboard Cite

Roughness down to atomic and close-to-atomic scale is receiving an increasing attention in recent studies of manufacturing development, which can be realized by high-precision polishing processes. This review presents polishing approaches at atomic and close-to-atomic scale on planar and curved surfaces, including chemical mechanical polishing, plasma-assisted polishing, catalyst-referred etching, bonnet polishing, elastic emission machining, ion beam figuring, magnetorheological finishing, and fluid jet polishing. These polishing approaches are discussed in detail in terms of removal mechanisms, polishing systems, and industrial applications. The authors also offer perspectives for future studies to address existing and potential challenges and promote technological progress.

show abstract

“…The surface roughness in the range of 1 Å–2 Å can be obtained throughout the fluid life and over a wide variety of machine types and wheel sizes. 94, 95 Recent advancements in MRF process make it suitable for improving low, mid- and high-spatial frequency errors to meet the ultra-high requirements of modern optics.…”

Section: Precision Finishing Techniques Used For Fabrication Of Opticmentioning

confidence: 99%

Review of several precision finishing processes for optics manufacturing

Ghosh

Sidpara

Bandyopadhyay

2018

Journal of Micromanufacturing

View full text Add to dashboard Cite

The ultrasmooth optical components with atomic-order surface roughness and nanometre-level shape accuracy are in immense demand with the rapid advancement of modern optical technology. In recent years, aspherical and free-form surfaces are gaining more interest for its favorable properties. Moreover, the new optical materials with immensely enhanced mechanical properties are being developed to meet the stringent requirements of modern optics. Fabrication of complex-shaped ultrasmooth optical components becomes a significant challenge as conventional finishing techniques are unable to machine aspherical or free-form surfaces precisely. This situation demands some highly deterministic finishing processes. Mostly, the optical components are fabricated by shaping or pre-finishing methods followed by final finishing processes. In the shaping or pre-finishing methods, the rigid abrasive tools are used to remove the material at an enhanced rate and near net shape of the elements can be attained. Surface finish and shape accuracy can also be improved to some extent. Owing to the presence of residual finishing marks generated by shaping methods, the application of the components is limited to the infrared (IR) optics. Final finishing processes include more deterministic and flexible polishing techniques that can achieve desired surface finish, figure accuracy and surface integrity to make it suitable for shorter wavelength applications. In recent years, single point diamond turning, precision grinding, plasma chemical vaporization machining and magnetorheological fluid-based finishing are widely used for fabricating ultrasmooth optics. In this article, principle, mechanism of material removal and applicability of the aforementioned precision finishing processes to different materials are discussed.

show abstract

Improving low, mid and high-spatial frequency errors on advanced aspherical and freeform optics with MRF

Cited by 16 publications

References 2 publications

Performance and limitations of using ELT and MCAO for 50 μas astrometry

Performance and limitations of using ELT and MCAO for 50 μas astrometry

Polishing Approaches at Atomic and Close-to-Atomic Scale

Review of several precision finishing processes for optics manufacturing

Contact Info

Product

Resources

About