title: Limits of diffractometric reconstruction of line gratings when using scalar diffraction theory.
abstract: We study errors that occur in geometry and phase reconstruction when using scalar diffraction theory in line gratings with periods below 10 μm. The application of those gratings in so-called computer-generated holograms in high-precision interferometric testing of aspheres and free-form surfaces imposes high demands on the generated phase, leading to error budgets in the range of λ/100. Using rigorous simulations as references, we identify the limits where scalar diffraction theory fails to accurately describe grating geometries and identify the significant error mechanisms.
authors: Sandy
authors: S
authors: Peterhänsel
authors: Christof
authors: C
authors: Pruss
authors: Wolfgang
authors: W
authors: Osten