Inventors:
Eberhard A. Spiller - Mount Kisco NY
Paul B. Mirkarimi - Sunol CA
Claude Montcalm - Livermore CA
Sasa Bajt - Sunol CA
James A. Folta - Livermore CA
Assignee:
The Regents of the University of California - Oakland CA
International Classification:
G02B 528
G02B 110
F21V 904
Abstract:
Stress compensating systems that reduces/compensates stress in a multilayer without loss in reflectivity, while reducing total film thickness compared to the earlier buffer-layer approach. The stress free multilayer systems contain multilayer systems with two different material combinations of opposite stress, where both systems give good reflectivity at the design wavelengths. The main advantage of the multilayer system design is that stress reduction does not require the deposition of any additional layers, as in the buffer layer approach. If the optical performance of the two systems at the design wavelength differ, the system with the poorer performance is deposited first, and then the system with better performance last, thus forming the top of the multilayer system. The components for the stress reducing layer are chosen among materials that have opposite stress to that of the preferred multilayer reflecting stack and simultaneously have optical constants that allow one to get good reflectivity at the design wavelength. For a wavelength of 13.