Effect of Spectral Diffusion on the Coherence Properties of a Single Quantum Emitter in Hexagonal Boron Nitride

Quantum emitters capable of producing single photons on-demand with high color purity are the building blocks of emerging schemes in secure quantum communications, quantum computing, and quantum metrology. Such solid-state systems, however, are usually prone to effects of spectral diffusion (SD), i.e., fast modulation of the emission wavelength due to the presence of localized, fluctuating electric fields. Two-dimensional materials are especially vulnerable to SD by virtue of the proximity of the emitters to the outside environment. In this study we report measurements of SD in a single hexagonal boron nitride (hBN) quantum emitter on the nanosecond to second time scales using photon correlation Fourier spectroscopy. We demonstrate that the spectral diffusion dynamics can be modeled by a two-component Gaussian random jump model, suggesting multiple sources of local fluctuations. We provide a lower limit of ∼0.13 for the ratio of the emitter’s coherence time (T2) to twice its radiative lifetime (2T1) when ...