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Title: Progress in ion figuring large optics

Conference ·
OSTI ID:552201
 [1]
  1. Eastman Kodak Company, Rochester, NY (United States)

Ion figuring is an optical fabrication method that provides deterministic surface figure error correction of previously polished surfaces by using a directed, inert and neutralized ion beam to physically sputter material from the optic surface. Considerable process development has been completed and numerous large optical elements have been successfully final figured using this process. The process has been demonstrated to be highly deterministic, capable of completing complex-shaped optical element configurations in only a few process iterations, and capable of achieving high-quality surface figure accuracy`s. A review of the neutral ion beam figuring process will be provided, along with discussion of processing results for several large optics. Most notably, processing of Keck 10 meter telescope primary mirror segments and correction of one other large optic where a convergence ratio greater than 50 was demonstrated during the past year will be discussed. Also, the process has been demonstrated on various optical materials, including fused silica, ULE, zerodur, silicon and chemically vapor deposited (CVD) silicon carbide. Where available, results of surface finish changes caused by the ion bombardment process will be discussed. Most data have shown only limited degradation of the optic surface finish, and that it is generally a function of the quality of mechanical polishing prior to ion figuring. Removals of from 5 to 10 {mu}m on some materials are acceptable without adversely altering the surface finish specularity.

Research Organization:
International Society for Optical Engineering, Washington, DC (United States)
OSTI ID:
552201
Report Number(s):
CONF-9410155-Vol.2428; TRN: 98:009014
Resource Relation:
Conference: 26. annual Boulder damage symposium: laser-induced damage in optical materials, Boulder, CO (United States), 24-26 Oct 1994; Other Information: PBD: [1995]; Related Information: Is Part Of Laser-induced damage in optical materials: 1994. Twenty-sixth annual Boulder damage symposium, proceedings; Bennett, H.E.; Guenther, A.H.; Kozlowski, M.R.; Newnam, B.E.; Soileau, M.J. [eds.]; PB: 722 p.
Country of Publication:
United States
Language:
English