Aspheric Surface Figuring Using Plasma Assisted Chemical Etching 

Corning-OCA Applied Optics, Inc. 

Garden Grove, CA 
 

This SBIR project resulted in a rapid, automated, low-cost method for the figuring of precision aspheric surfaces on fused silica optical elements

• Corning-OCA established pre- processing methods and a suitable Plasma Assisted Chemical Etching (PACE) removal depth strategy for fused silica to ensure that final PACE-finished surfaces meet current low-scatter optical standards
• Corning-OCA developed an accurate model for the PACE process on fused silica to precisely optimize the plasma etching tool path over the substrate surface to produce the desired correction
• Corning-OCA also designed and built a second generation PACE system which meets the material and electrical compatibility requirements imposed by the plasma etching process and demonstrated the capabilities of the final one-step PACE figuring method on a fused silica test substrate

• Lawrence Livermore National Laboratory has expressed a strong interest in PACE as a cost-effective fabrication technique for laser optics
• Norton Diamond Films, a primary player in the diamond coating market, has expressed interest in PACE’s figuring capability

• Potential applications include silicon aspheric figuring;  ultra-low scatter surfaces; silicon clad silicon carbide components; optical elements requiring zero subsurface damage; diamond thinning and figuring; and complex oxide thinning and figuring
• The basic methodology developed during this program can be readily optimized for additional materials, including silicon, germanium and others

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