| dc.description.abstract | Defects in the solid state have shown immense potential as single-quantum emitters (SQEs). An ideal SQE has photostable emission, high count rates, high single-photon purity, generates indistinguishable photons and operates at room temperature. However, to date, no solid-state defect meets all the criteria for an ideal SQE. Defects in hexagonal boron nitride (hBN), however, are promising defect candidates for use as SQEs given that they are some of the brightest SQEs on record, photostable at room temperature, and exhibit a high single-photon purity. However, there is a lack of scientific consensus in the degree of electron-phonon coupling and the energy structure in hBN SQEs. I first identify the phonon modes in hBN SQEs using a phenomenological model of the SQE microphotoluminescence (µPL) spectrum using Fermi’s golden rule. I then confirm the existence of optical phonon modes using two-color Hanbury Brown-Twiss (HBT) interferometry. Given this information, I investigate the excited state energy structure of hBN defects and provide evidence of photochromism in hBN SQEs with a combination of irradiation-time dependent measures of intensity, µPL spectroscopy, and two- color HBT interferometry. The results show that this hBN SQE exhibits two bright excited-state transitions. The cross-correlation measurements have for the first time enabled quantitative modeling of electron-phonon coupling in SQEs and photochromism in hBN SQEs. | |
