Microlithographic exposure apparatus

摘要

The disclosure relates to optical systems, such as illumination devices or projection objectives of microlithographic projection exposure apparatuses, that include at least one optical element having at least one curved lens surface which carries an interference layer system. The interference layer system includes an alternating sequence of layers. At least one of the layers is subdivided by at least one intermediate layer having a thickness of not more than 5 nanometers. A column structure which is formed in the at least one subdivided layer is interrupted by the at least one intermediate layer.