High-speed 2D materials inspection using a microscopic dynamic spectroscopic imaging ellipsometer

We describe a high-speed two-dimensional (2D) materials inspection method by using a microscopic dynamic spectroscopic imaging ellipsometer. This system employs a high-numerical-aperture (NA) objective telecentric lens module. Unlike conventional spectroscopic imaging ellipsometers, which require relatively long acquisition times due to rotating polarization elements, our proposed system uses a monolithic polarizing interferometric module. This allows it to extract a spatio-spectral ellipsometric phase map Δ( λ , x ) of 2D materials like graphene. It achieves a spatial resolution of a few microns at a speed of a few tens of milliseconds. In this study, we demonstrate that the proposed microscopic dynamic spectroscopic imaging ellipsometer can provide spectroscopic ellipsometric phase data Δ( λ ) with 165 spectral bands in the visible range. It inspects a monolayer graphene flake area of 2.5mm∗1.65mm in just 1 min, which is the fastest 2D materials inspection capability ever reported, to our knowledge.