A new optical technique for characterizing reference artefacts for surface profilometry

We compare two methods for characterizing the profile of surface relief diffraction gratings. First a Talystep and an atomic force microscope (AFM) are used to sense the surface and generate profiles that are a convolution of the stylus and the shape of the grating's surface. Second the reflectivity of the grating is scanned as a function of the angle of incidence. The shape of the observed anomalies, caused by radiation coupling to surface plasmons, depends critically on the groove profile and can be used to determine the true form of the surface. By comparing the optical and mechanical measurements we show that it is possible to determine the effective radius of curvature of the Talystep and AFM styli.