Figure 6: Tailoring plasmon-NV coupling in various hybrid ND–metal nanostructures.

(a) Dependence of the fluorescence lifetime of NV centres on the size of Ag nanoparticles in a hybrid ND–Ag nanostructure (corresponding materials control presented in Fig. 2a–f). Cyan: pure ND; green: ND–Ag (2.6 nm); orange: ND–Ag (4.1 nm); red: ND–Ag (6.0 nm). All ND–Ag hybrid nanostructures possess same surface coverage of Ag subunits (0.004 particles per nm²). (b) Dependence of the fluorescence lifetime of NV centres on the coverage of Ag nanoparticles in a hybrid ND–Ag nanostructure (corresponding materials control presented in Fig. 2g–l). Cyan: pure ND; green: 0.002 particles per nm²; orange: 0.012 particles per nm²; red: 0.195 particles per nm²; mean size of Ag subunits in all hybrid ND–Ag nanostructures is 4.5 nm. (c) Dependence of fluorescence lifetime of NV centres on the composition of metal nanoparticles in a hybrid ND based nanostructure (corresponding materials control presented in Fig. 3c). Cyan: pure ND; dark yellow: ND–Au; pink: ND–Ag. Surface coverage density of both ND–Au and ND–Ag hybrid nanostructures is 0.008 particles per nm².