Color-Dependent Laser Ablation Behavior of Diamonds: Microgroove Geometry and Surface Chemical Evolution

Laser ablation of diamond involves coupled thermal and chemical processes sensitive to intrinsic defects and ambient environments. Here, the color-dependent ablation behavior of diamonds is systematically investigated under nitrogen, air, and oxygen atmospheres. Ablation efficiency increases from colorless to black diamonds, attributed to enhanced laser absorption and localized thermal accumulation induced by higher defect densities. Meanwhile, atmospheric conditions regulate carbon transformation pathways. Raman results show a decrease in the ID/IG ratio from nitrogen to oxygen, indicating suppressed accumulation of disordered sp 2 carbon in oxidative environments. In contrast, XPS reveals increased C═C bonding and oxygen-containing functional groups with higher oxygen content. This discrepancy arises because Raman and XPS probe structural disorder and chemical composition, respectively. A competitive mechanism is proposed, where graphitization dominates in inert atmospheres, while oxidation removes unstable carbon and promotes surface reconstruction in oxygen-rich environments.