Optical measurement of the global and local geometry of grating structures

Advancement in the areas of lithography and holography have enabled the realization of very fine surface-relief grating structures in the nanometer to micrometer range. The characterization of such structures is of obvious importance. Different methods exist to determine the optical properties of gratings. The dispersion properties are typically analysed by spectrometers. The wavefront quality is measured by commercially available interferometers. The diffraction efficiency can be determined by scanning the far-field intensity distribution.