Abstract: An apparatus for measuring a curvature of a surface (1), comprising means for irradiating a first light beam (S1), a second light beam (S2) and a third light beam (S3) onto a surface (1) of a sample (12), a detector (5) comprising at least one detector plane and being adapted to detect a first position of the reflected first light beam (S1), a second position of the reflected second light beam (S2) and a third position of the reflected third light beam (S3) in the at least one detector plane, means for determining a first distance between the first position of the first light beam (S1) and the third position of the third light beam (S3) and a second distance between the second position of the second light beam (S2) and the third position of the third light beam (S3), and means for determining a mean curvature of the surface from the first distance and the second distance.

Abstract: A pyrometer that is adapted for detecting radiation in the range of 250 to 450 nm is disclosed. The pyrometer can be used for determining the temperature of a matter thermally emitting only ultraviolet-radiation. In particular, the pyrometer can include: a detector having an active area adapted for measuring thermal radiation, a longpass filter having a cut-off wavelength in the range of 400 to 450 nm, means adapted for alternately activating and deactivating the longpass filter, means adapted for measuring a first thermal radiation signal when the longpass filter is deactivated and adapted for measuring a second thermal radiation signal when the longpass filter is activated, and means adapted for determining a temperature corresponding to the measured thermal radiation from a difference of the first radiation signal and the second radiation signal.

Abstract: A method for calibrating a pyrometer a temperature of a calibration sample is determined from the ratio of a first reflectance and a second reflectance and the pyrometer is calibrated by assigning the determined temperature of the calibration sample with a thermal radiation signal measured by the pyrometer.

Abstract: The present invention relates to a method and an apparatus for determining the layer thickness and the refractive index of a sample. It is an object of the present invention to provide a method for determining the layer thickness of a sample (layer) having high light scattering characteristics that allows a fast (real-time process) and cost-effective measurement having a high accuracy.