The bright white emission from μ-diamonds

摘要

The synthetic μ-diamonds powder was synthesized using high pressure high temperature technique. The metal-catalyst effect was used to reduce the pressure and temperature of diamonds synthesis. The irradiation of diamonds by focused beam of 975 nm laser diode lead to obtain intense broadband white emission with maximum at 620 nm. This type of white emission generation were described earlier for graphene ceramic and graphene foam. The emission of μ-diamonds is characterized by low threshold of power excitation and strong dependence of ambient pressure. It was suggested that the white light emission observed from graphene samples may originate from the laser-induced sp~2↔sp~3 hybridization change as a result of the mechanism analogous to the intervalence charge transfer in Sr_2CeO_4 nanocrystals. Similar sp~2↔sp~3 hybridization change can occur in μ-diamonds resulting in intense, bright white light emission.