Picosecond-laser bulk modification induced enhancement of nitrogen-vacancy luminescence in diamond

We report on the enhancement of nitrogen-vacancy (NV) luminescence induced by the bulk structure modification of a type IIa single-crystal diamond with a visible picosecond laser. Using online monitoring of picosecondlaser-induced photoluminescence (PL) in the bulk regions we found that the integrated intensity of the NV PL is significantly increased after the bulk microstructure formation. The confocal PL spectroscopy investigations of the bulk microstructures have evidenced the enhanced NV luminescence and the splitting of the NV-emission. The increased concentration of the NV defects during picosecond-laser bulk modification correlates with the formation of sp(3) carbon allotropic structures and other defect centers revealed in PL/Raman spectra of high-stress regions near the fabricated microstructures. (C) 2016 Optical Society of America