Stephanie Fraser
University of Cambridge – Cambridge, England
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Following recent discovery of bright and robust single photon emitters in hexagonal boron nitride (hBN), this material has emerged as a promising platform for solid-state quantum technologies. Quantum correlation measurements confirm the high single-photon purity of several emitters. We propose that the observed magnetic field- and excitation power-dependent variations in photon bunching dynamics are governed by an electronic model featuring a ground state spin triplet manifold coupled to a metastable dark state, describing an optically addressable spin-active defect. Dephasing mechanisms – including spectral diffusion – limit the optical (and spin) coherence of these defects. Room-temperature photoluminescence spectra reveal a Lorentzian zero-phonon line centred around 590 nm. Our analysis suggests phonon broadening is the main source of linewidth broadening: though charge noise is likely to become dominant at cryogenic temperatures. Current efforts are focused on fabricating van der Waals heterostructures to enable electrostatic gating of hBN emitters, with the aim of suppressing charge noise and reducing linewidth broadening for improved quantum coherence.
Email: saf69@cam.ac.uk