SEDL / STP / STP689-EB / STP39106S

Optical Properties of KCl Forged between Optically Polished Dies

Anderson, RH
Honeywell Corporate Material Sciences Center, Bloomington, MN.

Bennett, JM
Honeywell Corporate Material Sciences Center, Bloomington, MN.

Pages: 5    Published: Jan 1979

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Abstract

Plano-plano and plano-concave KCl optcial elements have been isostatically forged using a two-step forging process in a closed die. No optical polishing was required for the finished surfaces. The initial forging was performed between teflon sheets, the sample was then water polished, and the final forging was done between optically figured fused quartz or pyrex dies. Forgings were typically done in the 200 to 275°C temperature range in a helium atmosphere at 29.65 MN/m² (4000 psi). Measurements on the finished samples include optical figure, homogeneity, internal strain, total integrated forward and backscattering, surface texture (Nomarski microscopy), and surface roughness. The results of these measurements are compared with similar measurements on optically polished single-crystal and press-forged KCl samples.