Plasmon-enhanced photoluminescence of Si-V centers in diamond from a nanoassembled metal–diamond hybrid structure

Using a facile top-down etching approach, a subwavelength-sized diamond pit structure infilled with semi-ellipsoidal gold nanoparticles was fabricated. The three-dimensional finite-difference time-domain simulations reveal strong localized surface plasmon resonance (LSPR) scattering and enhanced electric field exhibited by this hybrid nanoassembled metal–diamond-pit. Experimentally, with excitation at 633 and 830 nm close to the calculated LSPR wavelength, the photoluminescence (PL) intensities of the peak at 738 nm originating from the single photon source of silicon-vacancy centers in diamond were significantly enhanced by factors of ~100 and ~50, respectively, with respect to that from normal Si-doped diamond without the hybrid structure. By means of time-resolved PL measurements, the decay kinetic mechanisms of the plasmon-related PL enhancement were investigated and are discussed.