Limits of Brewster Angle Microscopy applied to thin films

Abstract

We explore the limits of Brewster Angle Microscopy (BAM) that may open up other possible applications of the technique. BAM is one of the most widely used imaging tools in the study of monolayer of supramolecular systems at water-air interface. Here, we study factors that may be important for other thin films such as dielectric and metallic oxide films on dielectric substrate. For a system that follows n_air < n_{thin film} < n_substrate, we show that Brewster imaging has a definite working thickness range so that the intensity response to a thickness value is unique. In our calculations, we also discuss how to maximize the the signal-to-noise ratio based on the indices of refraction of thin film and substrate.