Super-polishing of Zerodur aspheres by means of conventional polishing technology

Abstract

This paper describes a quest to find simple technique to superpolish Zerodur asphere (55µm departure from best fit sphere) that could be employed on old fashion way 1-excenter optical polishing machine. The work focuses on selection of polishing technology, study of different polishing slurries and optimization of polishing setup. It is demonstrated that either by use of fine colloidal CeO 2 slurry or by use of bowl-feed polishing setup with CeO 2 charged pitch we could reach 0.4nm RMS roughness while removing <30nm of surface layer. This technique, although not optimized, was successfully used to improve surface roughness on already prepolished Zerodur aspheres without necessity to involve sophisticated super-polishing technology and highly trained manpower.

Occurrence of Cerium-, Titanium-, and Silver-Bearing Nanoparticles in the Besòs and Ebro Rivers

“…All three are commonly listed among the most commonly employed engineered NMs, and their effects on the aquatic environment are under study. 16,17 cosmetics and paints, and as food additives because of their UV-absorbing properties; 18 Ag-NPs (nanosilver) are commonly employed in coatings, clothes, 19 in medicine 20 because of their bactericidal activity, and CeO 2 NPs are used as an abrasive for polishing surfaces 21 and as an additive in fuel for automobiles. 22,23 Wastewater treatment plants (WWTP) are considered as the main route of entry of these and other engineered NMs into the aquatic environment.…”

“…The present work focuses on titanium-bearing NPs (Ti-NPs), silver-bearing NPs (Ag-NPs), and cerium-bearing NPs (Ce-NPs). All three are commonly listed among the most commonly employed engineered NMs, and their effects on the aquatic environment are under study. , TiO 2 NPs are mass-produced and widely employed in cosmetics and paints, and as food additives because of their UV-absorbing properties; Ag-NPs (nanosilver) are commonly employed in coatings, clothes, in medicine because of their bactericidal activity, and CeO 2 NPs are used as an abrasive for polishing surfaces and as an additive in fuel for automobiles. , …”

Experimental power spectral density analysis for mid- to high-spatial frequency surface error control

“…Smoothing experiments using different polishing processes to control the RMS surface roughness value have previously been reported [4][5][6][7][8][9][10][11][12][13][14]. Most have focused on measurements within an area of ≤1 mm 2 , and have only compared RMS surface roughness values (the collapsed or integrated information of the fundamental PSD functions) for different methods.…”