This microscopy technique allows the direct observation of ultrathin organic films on transparent dielectric substrates. It is based on the effect that from the clean surface no reflection occurs when p-polarized incoming light under the Brewster angle. The "black background" of the Brewster Angle setup allows using the detector (CCD-camera) with the maximum of intensity. A very thin organic layer (e.g. a monolayer with typ. 2 nm) with different refractive index will cause reflection. Typically, the resulting reflection is only about a millionth of the incident intensity.
The reflected light can be used to form a high contrast image of the lateral morphology of the layer, with applications in the life sciences and materials research.