Abstract

We used surface thermal lensing (STL) to measure the weak absorption of optical films. Different trends of STL phase signals were observed in films with two types of defect, i.e., absorptive defects and heat-resistant defects. Theoretical analysis was made, and it is in good agreement with the experimental results. Therefore, an enhanced STL technique is proposed to deduce both the magnitude of absorption and the type of defect in optical films, by considering signal intensity with its phase status.

© 2010 Optical Society of America