Energy beam-based direct and assisted polishing techniques for diamond: A review

Diamond is a highly valuable material with diverse industrial applications, particularly in the fields of semiconductor, optics, and high-power electronics. However, its high hardness and chemical stability make it difficult to realize high-efficiency and ultra-low damage machining of diamond. To address these challenges, several polishing methods have been developed for both single crystal diamond (SCD) and polycrystalline diamond (PCD), including mechanical, chemical, laser, and ion beam processing methods. In this review, the characteristics and application scope of various polishing technologies for SCD and PCD are highlighted. Specifically, various energy beam-based direct and assisted polishing technologies, such as laser polishing, ion beam polishing, plasma-assisted polishing, and laser-assisted polishing, are summarized. The current research progress, material removal mechanism, and influencing factors of each polishing technology are analyzed. Although some of these methods can achieve high material removal rates or reduce surface roughness, no single method can meet all the requirements. Finally, the future development prospects and application directions of different polishing technologies are presented. The existing hurdles and various techniques for polishing diamond are summarized.Laser, ion beam, plasma-assisted, and laser-assisted polishing methods are reviewed.Material removal mechanism and influencing factors of various techniques are stated.Future directions of energy beam polishing techniques for diamond are discussed.Plasma-assisted polishing is suitable to get high-quality large diamond substrates.