Effects of Au nanoparticles on photoluminescence emission from Si-vacancy in diamond

► Coupling of Si centers of diamonds with plasmonic Au nanoparticles (NPs) was analyzed. ► AuNPs perfectly coupled with the laser source and the 738 nm PL band were used. ► Si-diamond PL shows an enhanced emission when coupled with the larger AuNPs. ► PL had a laser-like shape, with a threshold and a decrease of the FWHM vs pumping. ► A feedback resonance mechanism was discussed.