Abstract

The reactive sputtering technique provides an attractive approach for the fabrication of rugate filters. Such complex filters usually require a great deal of care in process control, to the extent of integrating some measured characteristic of the product such as optical reflectivity into the control algorithms. The general acceptance of rugate filters as commercial products has been hampered by these complexities of process control and by the difficulties of transitioning lessons learned in small scale research facilities to large scale box-coaters. Significant advances have recently been made in the development of planar magnetron sources and their associated power supplies. The technology provides for benefits in source stability, high deposition rates, high uniformity and under the correct conditions, allows sufficient ion bombardment of the growing film to achieve full densification at temperatures close to ambient.

© 1998 Optical Society of America