Abstract

Pulsed-laser-induced damage of optical thin films, in general are initiated by the absorption of laser radiation within the film bulk or at the interfaces between the film layers itself or the substrate. In the nanosecond pulse region, a heat flow analysis demonstrates the importance of thermophysical parameters of both the thin film host and the substrate. Especially, the thermal conductivity often shows, caused by thin film micro-structure, a deviating behavior, of instance anisotropy and compared to the bulk extremely low values.¹-³ We demonstrate the ingluence of thermal properties on the measurement of extremely low thin film absorption as well as their measurement by the help of the photothermal surface displacement technique.⁴,⁵ The experimental technique should be advantageously, because the measurement can be performed completely contactless, nondestructively and spatially high-resolved.

© 1990 Optical Society of America