Review of research on ultra-low surface scattering measurement for optical components

The continuous improvement in the manufacturing precision of advanced optical components, coupled with the rapid development of applications such as high-power laser systems, deep ultraviolet/extreme ultraviolet lithography equipment, and space-based gravitational wave detection telescopes, has imposed higher requirements on the surface characteristics of optical components. The demand for ultra-low surface scattering measurement of optical components has extended from laboratory research to industrial production, with increasingly stringent requirements for measurement sensitivity, accuracy, and spectral coverage. Against this backdrop, ultra-low surface scattering measurement techniques have become one of the key factors in breaking through the performance limits of optical components. Although significant advances have been made in theoretical modeling and instrument development of ultra-low surface scattering measurement technology, challenges remain, including difficulties in industrial adaptation, fragmented scattering data formats, and non-consistent measurement accuracy standards. In this paper the basic concepts of surface scattering are introduced, the research progress in surface scattering measurement of optical components both domestically and internationally is reviewed, and the breakthroughs of cavity ring-down spectroscopy in ultra-low surface scattering measurement of highly reflective components are analyzed. We focus on the ultra-low surface scattering measurement of optical surfaces and aim to provide insights for the development and application of ultra-low surface scattering measurement technology for optical surfaces.