11 November 1999 Vibration-compensated interferometer for measuring cryogenic mirrors
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Abstract
An advanced interferometer was built for measuring large mirrors at cryogenic temperatures. This instrument uses active control to compensate the effects of vibration to allow high resolution phase shift interferometry. A digital signal processor and high speed phase control from an electro-optic modulator allow phase measurements at 4000 Hz. These measurements are fed back to a real time servo in the DSP that provides a vibration-corrected phase ramp for the surface measurements taken at video rates. This instrument is planned to be integrated at NASA Marshall Space Flight Center's X-ray Calibration Facility for measuring NGST mirrors at 40 K.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Chunyu Zhao, James H. Burge, "Vibration-compensated interferometer for measuring cryogenic mirrors", Proc. SPIE 3782, Optical Manufacturing and Testing III, (11 November 1999); doi: 10.1117/12.369217; https://doi.org/10.1117/12.369217
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