7 February 2006 MRF applications: measurement of process-dependent subsurface damage in optical materials using the MRF wedge technique
Author Affiliations +
Abstract
Understanding the behavior of fractures and subsurface damage in the processes used during optic fabrication plays a key role in determining the final quality of the optical surface finish. During the early stages of surface preparation, brittle grinding processes induce fractures at or near an optical surface whose range can extend from depths of a few μm to hundreds of μm depending upon the process and tooling being employed. Controlling the occurrence, structure, and propagation of these sites during subsequent grinding and polishing operations is highly desirable if one wishes to obtain high-quality surfaces that are free of such artifacts. Over the past year, our team has made significant strides in developing a diagnostic technique that combines magnetorheological finishing (MRF) and scanning optical microscopy to measure and characterize subsurface damage in optical materials. The technique takes advantage of the unique nature of MRF to polish a prescribed large-area wedge into the optical surface without propagating existing damage or introducing new damage. The polished wedge is then analyzed to quantify subsurface damage as a function of depth from the original surface. Large-area measurement using scanning optical microscopy provides for improved accuracy and reliability over methods such as the COM ball-dimple technique. Examples of the technique's use will be presented that illustrate the behavior of subsurface damage in fused silica that arises during a variety of intermediate optical fabrication process steps.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Joseph A. Menapace, Pete J. Davis, William A. Steele, Lana L. Wong, Tayyab I. Suratwala, Philip E. Miller, "MRF applications: measurement of process-dependent subsurface damage in optical materials using the MRF wedge technique", Proc. SPIE 5991, Laser-Induced Damage in Optical Materials: 2005, 599103 (7 February 2006); doi: 10.1117/12.638839; https://doi.org/10.1117/12.638839
PROCEEDINGS
11 PAGES


SHARE
RELATED CONTENT

Deformation of fused silica: nanoindentation and densification
Proceedings of SPIE (September 23 1998)
Building high-damage-threshold surfaces at 351 nm
Proceedings of SPIE (February 26 2004)
Generating, Grinding And Figuring Advanced Optical Elements
Proceedings of SPIE (October 13 1986)
Noncontact estimate of grinding-induced subsurface damage
Proceedings of SPIE (November 11 1999)
Inverse topographic analysis of scratches
Proceedings of SPIE (December 22 2003)
The distribution of subsurface damage in fused silica
Proceedings of SPIE (February 07 2006)

Back to Top