Optical characterization of thin layers grown on metal components

F. Mayrhofer; G. Zauner; G. Hendorfer; G. Darilion; T. Müller

doi:10.1117/12.781108

28 April 2008 Optical characterization of thin layers grown on metal components

F. Mayrhofer, G. Zauner, G. Hendorfer, G. Darilion, T. Müller

Proceedings Volume 7003, Optical Sensors 2008; 70030R (2008) https://doi.org/10.1117/12.781108
Event: SPIE Photonics Europe, 2008, Strasbourg, France

Abstract

In this work a new method for calculating the optical properties of an absorbing film grown on substrates, including the real and imaginary part of the index of refraction is shown. In particular the thermal radiation of a growing oxide-film on a heated steel specimen is measured by a CCD camera with a near infrared (1000nm) band-pass filter. The observed radiation-signal shows significant temporal patterns due to interferences in the growing oxide film. Under the assumptions of known specimen temperature, constant optical properties (dielectric functions) of each layer and semitransparent films, it is possible to develop a model by which variations of the resulting emissivity with varying film-thickness can be explained. From this model, which is derived from the calculation of the reflectance of a thin absorbing film on an absorbing substrate, the complex index of refraction of the film can be determined without explicit knowledge of the optical constants of the respective layers. Since a matrix-camera is used to monitor the process changes of the emissivity over time, spatial information may also be derived. In this way it is possible to detect spatial inhomogeneities in the film and to determine the cause (either inhomogeneous growth rates or spatial variations of material properties). In addition, these results can be used for emissivity correction in non-contact thermal imaging. This method is not limited to oxide films and can be used for other heat treatment processes that deposit semitransparent films as well.

Citation Download Citation

F. Mayrhofer, G. Zauner, G. Hendorfer, G. Darilion, and T. Müller "Optical characterization of thin layers grown on metal components", Proc. SPIE 7003, Optical Sensors 2008, 70030R (28 April 2008); https://doi.org/10.1117/12.781108

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available