For building gravitational wave detectors large interferometer mirrors with extreme low total losses, especially low absorption losses are required. With Ion Beam Sputter Technology total losses of a few ten ppm are standard on small substrates e.g. 1 inch diameter. For the optimization of thickness uniformity on large substrates, a special double masking technique has been introduced into the coating process. Recent results for the losses of large optics at 512 nm are presented. The thickness uniformity on a 240 mm diameter substrate including the mirror center is better than +/- 0.25%. The contribution of the HR coatings to the spherical aberration of the mirrors is of the order of (lambda) /100. The absorption losses are typically below 2 ppm. The total losses are typically below 25 ppm.

Date Published: 4 November 1994
PDF: 6 pages
Proc. SPIE 2253, Optical Interference Coatings, (4 November 1994); doi: 10.1117/12.192135

Published in SPIE Proceedings Vol. 2253:
Optical Interference Coatings
Florin Abeles, Editor(s)