Measuring the thickness of few-layer graphene by laser scanning microscopy

This paper demonstrates laser scanning microscopy (LSM) as a viable means for quantitative and accurate measurement of reflectivity of microscopic objects/samples with diffraction-limited spatial resolution. As an example, the LSM technique along with the quantized nature of reflectivity in graphene are utilized to identify and count the number of layers of graphene few-layer flakes based on their thickness-dependent reflectivity contrast. The physical mechanism of LSM reflectivity and the associated data analysis techniques are concisely presented.