Optical two-dimensional coherent spectroscopy of color-center arrays in diamond

Defect-induced color centers in solids are promising candidates for applications in quantum information science. Quantum sensing applications and quantum-logic operations can utilize quantum entanglements mediated by coherent coupling between color centers. Therefore, a critical step is to enable deterministic coherent coupling of individual optically addressable color centers. This work reports our effort of probing coupling between SiV color centers by using optical two-dimensional coherent spectroscopy (2DCS), a technique that provides an extremely sensitive and background-free detection of coupling. Arrays of SiV color centers were fabricated by implanting Si ions into a diamond substrate with a focused ion beam. Optical 2DCS measurements on these color center arrays revealed coherent coupling between single color centers.