Computer-generated hologram (CGH), as well as methods for characterizing the surface shape of an optical element

摘要

The invention relates to a computer-generated hologram (CGH) and to a method for characterizing the surface shape of an optical element. According to one aspect, a CGH has a first region (121, 321, 421) having at least one useful structure (A) and a second region (122, 322, 422) spatially separated from this first region (121, 321, 421) this second area forms a control area for detecting a contamination forming on the CGH (120, 320, 420, 520).