Controlling single rare earth ion emission in an electro-optical nanocavity

Probing single rare earth ions is highly desirable for several quantum applications, but it is difficult due to low emission rates. Here, the authors demonstrate the detection and control of single Erbium ions emission using electro-optically active photonic crystal cavities patterned from thin-film lithium niobate. Rare earth emitters enable critical quantum resources including spin qubits, single photon sources, and quantum memories. Yet, probing of single ions remains challenging due to low emission rate of their intra-4f optical transitions. One feasible approach is through Purcell-enhanced emission in optical cavities. The ability to modulate cavity-ion coupling in real-time will further elevate the capacity of such systems. Here, we demonstrate direct control of single ion emission by embedding erbium dopants in an electro-optically active photonic crystal cavity patterned from thin-film lithium niobate. Purcell factor over 170 enables single ion detection, which is verified by second-order autocorrelation measurement. Dynamic control of emission rate is realized by leveraging electro-optic tuning of resonance frequency. Using this feature, storage, and retrieval of single ion excitation is further demonstrated, without perturbing the emission characteristics. These results promise new opportunities for controllable single-photon sources and efficient spin-photon interfaces.

Automated summary

The authors demonstrate the detection and control of single Erbium ions emission using electro-optically active photonic crystal cavities made from thin-film lithium niobate. Purcell-enhanced emission in optical cavities is utilized to probe single ions with low emission rates, and dynamic control of emission rate is achieved through electro-optic tuning of resonance frequency. These results provide promising opportunities for controllable single-photon sources and efficient spin-photon interfaces.