Fabrication Of Aspheric Germanium-Lens Surfaces By Ion Milling

Podzimek, O.; Beckmann, Leo H. J. F.; Brok, Jacco

doi:10.1117/12.938469

Cited by 4 publications

(2 citation statements)

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“…MRF [12] and ion-milling [13] provide successful state-ofthe-art asphere surface finishing technologies. The MRF process routinely polishes surfaces to so-called 'super polish' leaving microroughness of the surface (parameter Ra) well below 1 nm [10].…”

Section: Mrf and Ion-milling Aspheric Surface Finishingmentioning

confidence: 99%

Ultra-smooth finishing of aspheric surfaces using CAST technology

Kong¹,

Young²

2014

Advanced Optical Technologies

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Abstract:Growing applications for astronomical groundbased adaptive systems and air-born telescope systems demand complex optical surface designs combined with ultra-smooth finishing. The use of more sophisticated and accurate optics, especially aspheric ones, allows for shorter optical trains with smaller sizes and a reduced number of components. This in turn reduces fabrication and alignment time and costs. These aspheric components include the following: steep surfaces with large aspheric departures; more complex surface feature designs like stand-alone off-axis-parabola (OAP) and free form optics that combine surface complexity with a requirement for ultra-high smoothness, as well as special optic materials such as lightweight silicon carbide (SiC) for air-born systems. Various fabrication technologies for finishing ultra-smooth aspheric surfaces are progressing to meet these growing and demanding challenges, especially Magnetorheological Finishing (MRF) and ion-milling. These methods have demonstrated some good success as well as a certain level of limitations. Amongst them, computer-controlled asphere surface-finishing technology (CAST), developed by Precision Asphere Inc. (PAI), plays an important role in a cost effective manufacturing environment and has successfully delivered numerous products for the applications mentioned above. One of the most recent successes is the Gemini Planet Imager (GPI), the world's most powerful planet-hunting instrument, with critical aspheric components (seven OAPs and free form optics) made using CAST technology. GPI showed off its first images in a press release on January 7, 2014 . This paper reviews features of today's technologies in handling the ultra-smooth aspheric optics, especially the capabilities of CAST on these challenging products. As examples, three groups of aspheres deployed in astronomical optics systems, both polished and finished using CAST, will be discussed in detail.

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Section: Mrf and Ion-milling Aspheric Surface Finishingmentioning

confidence: 99%

Ultra-smooth finishing of aspheric surfaces using CAST technology

Kong¹,

Young²

2014

Advanced Optical Technologies

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show abstract

“…The selection of λ is arbitrary. An optimization algorithm such as the simplex method can be used to find the dwell times that satisfy the above requirements [6,7]. Due to the ill-conditioned matrix A, the solution is a compromise between residual error and smoothness [8][9][10][11].…”

Section: Linear Regularization Methodsmentioning

confidence: 99%