Simulation of a strain-coupled dark state in silicon-vacancy centers in diamond

Negatively charged silicon-vacancy (SiV^-) centers have been of interest in recent years due to properties such as a strong zero-phonon line and long spin coherence times that are potentially useful in quantum devices. In conjunction with this interest, there is a need to better understand the ways in which SiV^- centers are affected by sample strain and disorder. Previous studies by our group have demonstrated progress to address this question by means of analyzing a high-density SiV^- center ensemble using optical multidimensional coherent spectroscopy (MDCS) with both heterodyne and photoluminescence (PL) detection schemes [1]. The heterodyne-detected spectrum showed more than 60 times as much inhomogeneous broadening as the PL detected spectrum. A follow-up simulation [2] suggested that the broadening was due to inhomogeneous strain but did not explain the reason for differing results between PL and heterodyne detection schemes. Here, we demonstrate by simulation that this difference could be caused by strain-coupled, non-radiative transitions to a previously undetected dark state. The results of these simulations could be useful in the construction of devices where strain is used to intentionally modulate radiative emission effects.

[1] C. L. Smallwood, et al., Phys. Rev. Lett. 126, 213601 (2021).

[2] C. L. Smallwood, T. W. Chin, and K. M. Bates, APS March Meeting, Abstract M39.00001 (2023).