Microstructured optics for Excimer-based systems: Applications for imaging, beam shaping and coherence management

Imaging diffractive optical elements (DOEs), randomly distributed microlenses and sub-lambda-structures allow the improvement of the performance of Excimer-based imaging and illumination systems. Here we present the concept study of a hybrid imaging system for Excimer laser high power application at a working wavelength of 308 nm. In this hybrid approach a focus has to be put onto the impact of the non-desired diffraction orders to the optical performance and also to the amount of light remaining in the system and causing lens heating. Hereby the diffraction efficiency of the DOE is of enormous importance. Especially the influence of the passive facet of blazed transmission gratings has to be considered. For illumination systems we discuss the transfer of the uneven raw profile of an Excimer-laser into a Gaussian far-field distribution by introducing a microlens array with a 2-dimensional Voronoi-pattern. The holographic record of the microlens array allows additionally to influence the coherence parameters.