Electromagnetically induced transparency in inhomogeneously broadened divacancy defect ensembles in SiC

TL;DR

This paper demonstrates electromagnetically induced transparency (EIT) in inhomogeneously broadened divacancy ensembles in silicon carbide, showing potential for quantum sensing despite material complexities.

Contribution

It provides the first detailed analysis of EIT in multi-level, inhomogeneously broadened solid-state defect ensembles, with experimental validation and modeling.

Findings

High-visibility EIT achieved in SiC divacancy ensembles

Coherences established between different two-level systems all-optically

Model aligns with experimental results, indicating potential for quantum sensing

Abstract

Electromagnetically induced transparency (EIT) is a phenomenon that can provide strong and robust interfacing between optical signals and quantum coherence of electronic spins. In its archetypical form, mainly explored with atomic media, it uses a (near-)homogeneous ensemble of three-level systems, in which two low-energy spin-1/2 levels are coupled to a common optically excited state. We investigate the implementation of EIT with c-axis divacancy color centers in silicon carbide. While this material has attractive properties for quantum device technologies with near-IR optics, implementing EIT is complicated by the inhomogeneous broadening of the optical transitions throughout the ensemble and the presence of multiple ground-state levels. These may lead to darkening of the ensemble upon resonant optical excitation. Here, we show that EIT can be established with high visibility also in this material platform upon careful design of the measurement geometry. Comparison of our experimental results with a model based on the Lindblad equations indicates that we can create coherences between different sets of two levels all-optically in these systems, with potential impact for RF-free quantum sensing applications. Our work provides an understanding of EIT in multi-level systems with significant inhomogeneities, and our considerations are valid for a wide array of defects in semiconductors.