Why Silicon for Telescope Mirrors and Structures?

Roger A. Paquin, Douglas R. Mc Carter†
McCarter Machine Co., Inc., 1312 Underwood Rd., Deer Park, TX, USA 77536


Single crystal silicon (SCSi) is light, strong, has excellent thermal properties, is readily available and cost and delivery are competitive with, and probably better than, either beryllium or silicon carbide. In addition, SCSi’s zero-defect crystal structure enables polishing to near-perfect surfaces.

Recent developments in direct bonding have led to simple methods of attaching SCSi, a brittle material, to enhance its high compressive strength and avoid tensile/brittle failures. Dynamic testing of a bonded assembly has demonstrated high resonant frequencies and damping capacity. Other recent test results have shown the excellent temporal and thermal stability of both monolithic and bonded mirror specimens.

So why not choose silicon?

(Download the paper here or contact Doug McCarter at dmccarter@mccarteret.com.)