We present a novel method for determining both the thickness and the optical constants of a weakly absorbing thin film upon a nearly transparent substrate through analysis of transmittance measured at various incident angles with coherent light. We demonstrate this method for a polymer thin film. The refractive indices and extinction coefficients of poly(DRI-anthranilic acid) at wavelengths of 1064, 632.8, and 532 nm were determined for the first time to our knowledge. We also confirmed the validity of our method with a polystyrene thin film whose optical constant was known. It was found that a thickness of a few hundred nanometers can easily be measured and that this method offers simplicity as well as the capability of in situ measurement.
© 2002 Optical Society of America
(120.4530) Instrumentation, measurement, and metrology : Optical constants
(120.5240) Instrumentation, measurement, and metrology : Photometry
(120.7000) Instrumentation, measurement, and metrology : Transmission
(310.6860) Thin films : Thin films, optical properties
Changsoo Jung and Bum Ku Rhee, "Simultaneous determination of thickness and optical constants of polymer thin film by analyzing transmittance," Appl. Opt. 41, 3861-3865 (2002)