Stimulated Emission Depletion Spectroscopy of Color Centers in Hexagonal Boron Nitride

We demonstrate the use of Stimulated Emission Depletion (STED) spectroscopy to map the electron-optical-phonon sideband of the ground state of the radiative transition of color centers in hexagonal boron nitride emitting at 2.0-2.2 eV, with in-plane linear polarization. The measurements are compared to photoluminescence of excitation (PLE) spectra that maps the electron-optical-phonon sideband of the excited state. The main qualitative difference is a red-shift in the longitudinal optical phonon peak associated with E-1u symmetry at the zone center. We compare our results to theoretical work on different defect species in hBN and find they are consistent with a carbon-based defect.

Automated summary

The study demonstrates the use of STED spectroscopy to map the characteristics of color centers in hexagonal boron nitride. A red-shift in the phonon spectra of ground state and excited state was observed. The experimental results suggest a correlation with carbon-based defects.