High-accuracy surface figure measurement of silicon mirrors at 80 K

Peter N. Blake; Ronald G. Mink; John Chambers; F. David Robinson; David A. Content; Pamela Davila

doi:10.1117/12.551738

24 September 2004 High-accuracy surface figure measurement of silicon mirrors at 80 K

Peter N. Blake, Ronald G. Mink, John Chambers, F. David Robinson, David A. Content, Pamela Davila

Proceedings Volume 5494, Optical Fabrication, Metrology, and Material Advancements for Telescopes; (2004) https://doi.org/10.1117/12.551738
Event: SPIE Astronomical Telescopes + Instrumentation, 2004, Glasgow, United Kingdom

Abstract

This report describes the equipment, experimental methods, and first results at a new facility at the Goddard Space Flight Center Optics Branch for interferometric measurement of cryogenically-cooled spherical mirrors. A mirror is cooled to 80 K and 20 K within a cryostat; and its surface figure error is measured through a fused-silica window using standard phase-shifting interferometry. The first mirror tested was a concave spherical silicon foam-core mirror with a clear aperture of 120 mm. The optic surface was measured at room temperature outside the dewar using standard "absolute" techniques; and then the change in surface figure error within the dewar from room temperature to 80 K was measured, and the two measurements added to create a representation of the two-dimensional surface figure error at 80 K, with a combined standard uncertainty of 3.4 nm rms. The facility and techniques will be used to measure the surface figure error at 20K of prototype lightweight silicon carbide and Cesic mirrors developed by Galileo Avionica (Italy) for the European Space Agency (ESA).

Citation Download Citation

Peter N. Blake, Ronald G. Mink, John Chambers, F. David Robinson, David A. Content, and Pamela Davila "High-accuracy surface figure measurement of silicon mirrors at 80 K", Proc. SPIE 5494, Optical Fabrication, Metrology, and Material Advancements for Telescopes, (24 September 2004); https://doi.org/10.1117/12.551738

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