Morphogenesis of mesoscopic surface patterns formed in polarized two-photon etching of diamond

Optimised diamond to graphite conversion via a metastable sp1-bonded carbon chain formation under an ultra-short femtosecond (30 fs) laser irradiation

“…To date, the primary mechanisms underlying the sub-50 fs laser processing of diamond still remain poorly understood, including surface oxygen termination at, below, and above the diamond's ablation threshold, surface faceting, the sp 3 -to-sp 2 phase conversion rate, the quality and organisation of sp 2 graphitic fractions produced and, the factors leading to the formation of nanopatterns, including the laserinduced periodic surface structures (LIPSS) (aka. nano-ripples) [30,31] on the surface of diamond. Calvani et al [13] demonstrated that LIPSS features are not exclusive to laser converted sp 2 -rich nanopatterns on diamond but arise from laser light interactions with the surface and, importantly, do not necessitate sp 3 to sp 2 phase transformation to occur.…”