Coherent Interactions of Diamond Defect Centers Probed with Two-Dimensional Coherent Spectroscopy

Negatively charged silicon-vacancy (SiV⁻) centers in diamond are a promising platform for solid-state quantum technologies owing to their narrow optical transitions and compatibility with nanophotonic integration. While single-defect properties are well characterized, scalable architectures require controlled coupling between multiple emitters. Here, I employ collinear two-dimensional coherent spectroscopy (2DCS) to investigate dipole–dipole interactions and coherent coupling in SiV⁻ ensembles created via focused ion beam implantation. 2DCS separates homogeneous and inhomogeneous broadening, reveals correlations between transitions, and provides direct spectral signatures of coupling. Measurements spanning implantation densities from isolated defects to ensembles of 10³ centers per site reveal the crossover from individual emitter responses to collective many-body behavior. These findings establish 2DCS as a powerful probe of coherent interactions in diamond defect systems and yield critical insights for engineering coupled qubits in scalable quantum photonic devices.