Efficient Quasi-Resonant, Polarization-Selective Excitation of GaN Quantum Emitters

Abstract

Defect centers in GaN emerge as bright sources of single-photons which recently have been demonstrated to optically interface a localized spin. However, the structure and composition of these defects as well as their efficient excitation techniques were not a subject of thorough studies. This work presents evidence that by tuning the excitation laser energy to specific resonance values the excitation efficiency can be enhanced, resulting in relative increase of photoluminescence intensity by up to an order of magnitude. The resonances can be selectively addressed with linearly polarized light, while the emission dipole remains unchanged, enabling polarization-controlled enhancement. These results establish an efficient way of excitation for GaN-based emitters, thereby increasing the generation rate of photons. The data is consistent with excitation via localized vibrational modes associated with point-defect complexes, establishing a practical quasi-resonant route to brighter, polarization-addressable operation of GaN defect emitters and clarifying their energy-level structure.