Measuring amplitude and phase of light emerging from microstructures with HRIM
Ultra high-resolution measurements of amplitude and phase fields emerging from fine period amplitude gratings are presented and discussed. In the axial direction periodically repeated features are found, whose origins are the Talbot effect within the Fresnel diffraction regime. The phase field recording leads to a very precise measurement of the localization of the Talbot planes and precisions below 100 nm are demonstrated. The concept of immersion interference microscopy is demonstrated. By accessing the back focal plane of the observation system filtering of diffraction orders provides specific Talbot images and allows to intuitively understand the role of diffraction orders for Talbot effect.