Quantum Interference of Resonance Fluorescence from Germanium-Vacancy Color Centers in Diamond
Disheng Chen, Johannes E. Fröch, Shihao Ru, Hongbing Cai, Naizhou Wang, Giorgio Adamo, John A. Scott, Fuli Li, Nikolay I. Zheludev, Igor Aharonovich, Weibo Gao
Abstract
Resonance fluorescence from a quantum emitter is an ideal source to extract indistinguishable photons. By using the cross-polarization to suppress the laser scattering, we observed resonance fluorescence from GeV color centers in diamond at cryogenic temperature. The Fourier-transform-limited line width emission with T2/2T1 ∼ 0.86 allows for two-photon interference based on single GeV color center. Under pulsed excitation, the separated photons exhibit a Hong–Ou–Mandel quantum interference above classical limit, whereas the continuous-wave excitation leads to a coalescence time window of 1.05 radiative lifetime. In addition, we demonstrated a single-shot readout of spin states with a fidelity of 74%. Our experiments lay down the foundation for building a quantum network with GeV color centers in diamond.