Optical profilometry (confocal microscopy/interferometry) is a non-contact imaging method for observing and characterising the topography of surfaces over measurement ranges from tens of µm² to a few mm², with a lateral resolution of 200 nm and depth resolutions from nm to several mm. Conventional analysis provides 2D and 3D images of the surface with the dimensions of the observed features, as well as numerous roughness statistics.
Different modes can be used to access different levels of information. Confocal microscopy can image all types of samples (flat or very rough, slopes up to 70%). On smooth samples, interferometry allows to reach nanometric vertical resolutions.