Teflon polishing is compared with pitch polishing as a method for achieving supersmooth and flat optical surfaces. Because a Teflon lap wears slowly, it will retain its surface shape to produce extremely flat optical surfaces, λ/100, consistently and reliably for extended periods of time, of the order of days. To compare the two methods, we polished 50-mm-diameter samples of various optical materials, using colloidal suspensions in water on both pitch and Teflon laps under the same polishing conditions. Flatness was maintained to better than λ/10, and roughness less than 10 Å rms was measured on all samples by two Talystep surface-profiling instruments, one in the United States and one in Australia, with excellent agreement between measurements made by the two instruments. It was possible to obtain flat and smooth surfaces (<4-Å rms roughness) on all materials (except for F4, flint glass), but only certain combinations of material, abrasive, and lap could be used to give the correct polishing conditions and surface chemistry.
© 1992 Optical Society of AmericaFull Article | PDF Article
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