[分享] 独家重磅放出西安会议资料2:Manufacturing of precision optical coatings

[/free]Manufacturing of precision optical coatings
Markus K. Tilsch, Marius Grigonis, and Georg J. Ockenfuss
JDSU, Santa Rosa, CA 95407, USA
E-mail: Markus.Tilsch@jdsu.com
Thin film optical coatings tailor light reflected or transmitted from an optical element in a desired way. An optical coating chamber is a complex system in which multiple subsystems operate together to fabricate such coatings. For physical vapor deposition processes such as evaporation and sputtering, the active parts of these subsystems are located within a vacuum chamber. One example of such a subsystem is the source system which provides the vapor from which the films are formed. A gas delivery subsystem may add process gases in their ground state or in an excited state. Rotary motion and masking subsystems may be used to achieve better uniformity. A subsystem that ensures accurate layer thickness control may be employed. Precision optical coatings require that individual layer thicknesses be controlled to within a few percent of the design target or less to achieve the accurate placement of a spectral feature. Systems for manufacturing precision optical coatings demand the use of subsystems that perform within tight tolerances. We illustrate subsystem requirements by examining three examples in detail. We discuss the spectral placement impact that result from height variations of the substrate mounting, thermal gradients on a substrate, and process instabilities from a moving anode. We conclude by providing a few examples of the performance attainable using a precision coating platform when all subsystems work properly.[free]