Research Progress Of High-Precision Surface Metrology Of A K-B Mirror

The advanced light source represented by the new generation of the diffraction limit synchrotron radiation source and the full-coherent X-ray free-electron laser has become an indispensable research tool in many fields. The continuous development of advanced light sources drives the rapid progress of ultra-precision optical manufacturing. The surface precision of a K-B mirror, a key focusing optical element in advanced light sources, is an important factor, which should be less than tens of nano radians. However, high precision K-B mirror surface metrology still has great technical challenges and is now a research hotspot in the scientific community. This paper introduces typical K-B mirror surface metrology, including reflection profile measuring technology such as the Long Trace Profiler (LTP), the Nanometer Optical component Measuring (NOM), and stitching interference metrology. Current K-B mirror surface shape technologies are summarized and the upcoming research progress is prospected.