@article {677237,
	title = {Enhanced cavity coupling to silicon vacancies in 4H silicon carbide using laser irradiation and thermal annealing},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {118},
	number = {12},
	year = {2021},
	abstract = {The negatively charged silicon monovacancy\&nbsp;VSi{\textemdash} in 4H silicon carbide (SiC) is a spin-active point defect that has the potential to act as a qubit in solid-state quantum information applications. Photonic crystal cavities (PCCs) can augment the optical emission of the\&nbsp;VSi{\textemdash}, yet fine-tuning the defect{\textendash}cavity interaction remains challenging. We report on two postfabrication processes that result in enhancement of the\&nbsp;V1{\textquoteright} optical emission from our PCCs, an indication of improved coupling between the cavity and ensemble of silicon vacancies. Below-bandgap irradiation at 785-nm and 532-nm wavelengths carried out at times ranging from a few minutes to several hours results in stable enhancement of emission, believed to result from changing the relative ratio of\&nbsp;VSi0\&nbsp;({\textquotedblleft}dark state{\textquotedblright}) to\&nbsp;VSi{\textemdash}\&nbsp;({\textquotedblleft}bright state{\textquotedblright}). The much faster change effected by 532-nm irradiation may result from cooperative charge-state conversion due to proximal defects. Thermal annealing at 100 {\textdegree}C, carried out over 20 min, also results in emission enhancements and may be explained by the relatively low-activation energy diffusion of carbon interstitials\&nbsp;CiCi, subsequently recombining with other defects to create additional VSi{\textemdash}s. These PCC-enabled experiments reveal insights into defect modifications and interactions within a controlled, designated volume and indicate pathways to improved defect{\textendash}cavity interactions.},
	url = {https://www.pnas.org/content/118/12/e2021768118},
	author = {Mena N. Gadalla and Greenspon, Andrew S. and Defo, Rodrick Kuate and Zhang, Xingyu and Hu, Evelyn L.}
}
