Unveiling the Zero-Phonon Line of the Boron Vacancy Center by Cavity Enhanced Emission

Abstract

Negatively charged boron vacancies (V − B ) in hexagonal boron nitride (hBN) exhibit a broad emission spectrum due to strong electron-phonon coupling and Jahn-Teller mixing of electronic states. As such, the direct measurement of the zero-phonon line (ZPL) transition of V − B in pristine hBN crystals has remained elusive. Here, we measure the room-temperature ZPL wavelength of V − B to be 773 ± 2 nm by coupling the hBN layer to the discrete high-Q mode in a proximal Si 3 N 4 nanobeam cavity. As the wavelength of the cavity mode is tuned, we observe a pronounced intensity resonance, indicative of

Creation of optically addressable spin centers in hexagonal boron nitride by proton irradiation

“…2, a in an enlarged scale, corresponds to the zero phonon line of V − B -centers, as has been demonstrated previously in [32,33]. In particular, the maximum of this zero-phonon line in [33] was found to be equal to λ = 773 ± 2 nm. It should be noted that the hBN sample did not have the above-mentioned spectral singularities prior to proton irradiation, as can be seen from the init.…”

“…The weakly intensive peak in the PL spectrum with the maximum at the wavelength of λ = 772.4 nm, shown in the inset in Fig. 2, a in an enlarged scale, corresponds to the zero phonon line of V − B -centers, as has been demonstrated previously in [32,33]. In particular, the maximum of this zero-phonon line in [33] was found to be equal to λ = 773 ± 2 nm.…”

Effect of environmental screening and strain on optoelectronic properties of two-dimensional quantum defects

“…A large number of defects in hexagonal boron nitride (hBN) have been proposed since the report by Tran et al [7]. So far, spin defect V − B has been unambiguously identified from experiment [8][9][10][11] and theory [12,13]. Many of the other defects, whose atomic origins are yet to be determined, were found to be ∼2 and ∼4 eV SPEs [14][15][16][17].…”

Coupling spin defects in hexagonal boron nitride to titanium dioxide ring resonators

“…[16][17][18][19][20] However, the photoluminescence emission from V B − spans in the NIR has no clear indication of zero phonon line (ZPL) even at cryogenic temperature, and the exact electronic level structure and emission dipole of V B − are yet to be understood. Just recently, coupling of the defects into high-quality cavities suggests the ZPL spectral location to be around 770 nm 21 and excited state spectroscopy of the defects revealed the spin states in the excited state. [22][23][24] Moreover, the defect suffers from low intrinsic brightness and quantum efficiency.…”