Resonance fluorecence from single impurity-bound excitons in ZnSe

Impurity-bound excitons in II-VI semiconductors represent promising candidates for optically active solid-state spin qubits. While previous research show approaches that primarily utilized incoherent optical pump of these impurities, quantum technologies usually demand coherent excitation of the optical transitions. In this presentation, we show coherent pumping and resonance fluroescence emission from a single impurity-bound exciton in ZnSe, with the coherence of the emission demonstrated by a polarization interferometry. The resonant excitation further allows measurement of the Debye-Waller factor, which is determined to be 0.95, signifying highly efficient emission into the zero-phonon line among defect centers. Time-resolved measurements reveal ionization process and tunneling of the impurity. Additionally, we show that a low-power incoherent pump can stabilize the charge environment of the donor-bound exciton on the timescale of 9.3 ns. These results highlights the merits of bright emission properties of ZnSe, which paves the way towards the spin control of impurity-bound excitons in II-VI semiconductor.