Ultralightweight silicon carbide mirror design

Mark A. Ealey; John A. Wellman

doi:10.1117/12.258289

11 November 1996 Ultralightweight silicon carbide mirror design

Mark A. Ealey, John A. Wellman

Proceedings Volume 2857, Advanced Materials for Optical and Precision Structures; (1996) https://doi.org/10.1117/12.258289
Event: SPIE's 1996 International Symposium on Optical Science, Engineering, and Instrumentation, 1996, Denver, CO, United States

Abstract

Silicon carbide mirrors have been made ultra lightweight with an areal density below 10 kg/mm² and have been made in sizes as large as 1.2 meters in diameter. The CERAFORM SiC process provides a cost-effective means to make lightweight substrates in either the open back or closed back form. Optical finishes below 10 angstrom rms have been achieved on both the chemical vapor deposited beta phase and the silicon infiltrated alpha phase. COmplex structures with triangular, square, or hexagonal core geometry has been produced with web thicknesses as thin as 0.015 inches and depth to diameter aspect ratios as large as 50:1. By designing to specific sectional stiffness, SiC offers performance which exceeds that of beryllium and glass, especially in extreme thermal environments. By polishing bare CERAFORM SiC to better than 10 angstrom rms, the single greatest impediment to SiC being used as an optical material was resolved.

Citation Download Citation

Mark A. Ealey and John A. Wellman "Ultralightweight silicon carbide mirror design", Proc. SPIE 2857, Advanced Materials for Optical and Precision Structures, (11 November 1996); https://doi.org/10.1117/12.258289

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