Research on the fabrication of high-quality patterned diamond using femtosecond laser

Diamond, known for its exceptional thermal, electrical, and mechanical properties, is widely used in precision machining tools, MEMS, and electronic devices. However, because of its extreme hardness and chemical inertness, diamond machining is highly challenging. Femtosecond laser technology, with its high instantaneous energy and minimal heat-affected zone, has emerged as an effective method for the precision machining of diamond. This study explores the application of 1026 nm and 513 nm femtosecond lasers in diamond grooving. The experimental results indicate that with increasing laser energy density, both groove width and depth increase, accompanied by a rise in amorphous carbon and graphite contents, resulting in increased tensile stress and decreased crystallinity in the machined region. Notably, the 513 nm laser demonstrates higher precision, achieving narrower grooves suitable for fine machining of diamond. Molecular dynamics simulations and experimental data reveal that the formation of amorphous carbon and graphite phases is the primary mechanism for deep ablation, and no significant anisotropy is observed during the process, allowing for the uniform fabrication of micro-nanostructures. TEM analysis confirms the presence of amorphous carbon and nanocrystalline diamond at the groove bottom, indicating phase transformation and also the formation of nanoscale diamond particles in regions of concentrated femtosecond laser energy. This study provides experimental and theoretical support for the high-quality fabrication of micro-nano structures on diamond, with significant implications for its advanced applications.