▎ 摘　　要

Two different samples of graphene, multi-layer flakes on Si/SiO2 substrates and single layer graphene on glass, have been examined by reflectivity contrast and spatial modulation spectroscopy measurements. For the multi-layer graphene flakes, the reflectivity contrast and spatial modulation spectroscopy measurements are in good agreement, validating the application of spatial modulation spectroscopy to two-dimensional samples. The measurements for single layer graphene on glass show features that correspond to increases and decreases in reflectivity. The features with increased reflectivity are assigned to small regions of multilayer graphene or polymer, and the features with decreased reflectivity are assigned to holes in the graphene film. Using a model for thin film reflectivity we calculate the size dependent spatial modulation signal for the holes, and find that a significant number of holes have a larger than expected signal. This could arise from the presence of multi-layers of graphene in the sample, or because of optical resonance effects for the holes. (C) 2014 AIP Publishing LLC.