Metrology guided laser micromachining of SiC for mirrors

R. L. Jacobsen; M. B. Scott; J. Pitz; A. A. Goshtasby; J. Britton; D. Smith

doi:10.1117/12.734295

15 September 2007 Metrology guided laser micromachining of SiC for mirrors

R. L. Jacobsen, M. B. Scott, J. Pitz, A. A. Goshtasby, J. Britton, D. Smith

Proceedings Volume 6666, Optical Materials and Structures Technologies III; 666609 (2007) https://doi.org/10.1117/12.734295
Event: Optical Engineering + Applications, 2007, San Diego, California, United States

Abstract

Silicon carbide mirrors are sought for a variety of aerospace applications. While optical polishing techniques are straight forward for flat and spherical surfaces, material removal rates for this hard, brittle material are too low for affordable processing of conventionally machined, ground, or as-produced surfaces. The problem is more severe for aspheres. This paper reports on the use of picosecond pulsed laser ablation, combined with iterative metrology, to shape the SiC in a manner that will reduce cost and lead time for mirror fabrication. The goal is to exploit relatively gentle, non-thermal ablation to produce arbitrary surface shapes in SiC that are damage free and that minimize subsequent polishing time. To apply the technology, detailed data must be developed to characterize laser-material interaction, the threshold for ablation, and the dependence of the effective "tool shape" on laser operating parameters and firing patterns. An algorithm can then be developed to calculate optimum laser guidance and firing commands for removal of the required amount of material from the ceramic surface, with reference to metrology data previously collected on the mirror blank. Recent results of machining quality, material removal rates, residual surface roughness, and suitability of surface for subsequent polishing are reported for various types of SiC and paradigms of laser micromachining.

Citation Download Citation

R. L. Jacobsen, M. B. Scott, J. Pitz, A. A. Goshtasby, J. Britton, and D. Smith "Metrology guided laser micromachining of SiC for mirrors", Proc. SPIE 6666, Optical Materials and Structures Technologies III, 666609 (15 September 2007); https://doi.org/10.1117/12.734295

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available