LETTER TO THE EDITOR: On the limit to the resolution of photoreflectance techniques for sensing analyte concentration at surfaces

Abstract

We discuss the possibility of approaching a shot-noise-limited measurement of the difference reflectance due to analyte absorption or adsorption on the surface of a thin film, and estimate the resolution for a variety of cases. When using a 1 mW optical beam, the limit of resolution will commonly correspond to a small or very small fraction of a monolayer of the analyte.