We report a systematic investigation on the spectral splitting of negatively charged, nitrogen-vacancy (NV-) photo-luminescent emission in single crystal diamond induced by strain engineering. The stress fields arise from MeV ion-induced conversion o
f diamond to amorphous and graphitic material in regions proximal to the centers of interest. In low-nitrogen sectors of a HPHT diamond, clearly distinguishable spectral components in the NV- emission develop over a range of 4.8 THz corresponding to distinct alignment of sub-ensembles which were mapped with micron spatial resolution. This method provides opportunities for the creation and selection of aligned NV- centers for ensemble quantum information protocols.
