Studying polymer thin films with hybrid optical microcavities

Organic and inorganic polymeric thin films have numerous applications, including solar cells, biodetection, and nanocomposites. Improving our understanding of the fundamental material behavior is critical to designing polymers with ideal behavior and increased lifetime. However, there are limited nondestructive characterization methods that are able to perform these high-resolution measurements. In this Letter, we demonstrate a method that is able to detect temperature-induced changes in the refractive index of polystyrene polymer thin films as small as 10−7. This approach is based on optical microcavity resonators. The experimental results agree well with the theoretical simulations.