“Quantum Nanophotonics with Ytterbium in Yttrium Orthovanadate"
Abstract: Quantum light-matter interfaces that can reversibly map quantum information be- tween photons and atoms are essential for building future quantum networks. Rare- earth ions (REIs) in crystals are an attractive solid-state platform for such light-matter interfaces due to their exceptional optical and spin coherence properties at cryogenic temperatures. Building scalable REI-based technology has proven to be challenging due to the inherently weak coupling of REIs with light. In this talk, I will describe our efforts to integrate REIs with nanophotonic resonators to overcome this weak light-matter interaction and enable efficient, scalable quantum light-matter interfaces. Specifically, this talk will focus on the detection and coherent manipulation of single ytterbium ions coupled to nanophotonic cavities fabricated directly in the orthovanadate (YVO4) host crystal.
The Purcell-enhancement in these cavities enables efficient optical detection and spin initialization of individual ytterbium ions. We identify ions corresponding to different isotopes of ytterbium and show that the coupling of electron and nuclear spin in ytterbium-171 at zero-field gives rise to strong electron-spin transitions that are first-order insensitive to magnetic field fluctuations. This allows for coherent microwave control and the observation of long spin coherence lifetimes at temperatures up to 1 K. We then make use of the optical selection rules and energy structure of 171Yb:YVO4 to demonstrate high-fidelity single-shot optical readout of the spin state. These results establish nanophotonic devices in 171Yb:YVO4 as a promising platform for solid-state quantum light-matter interfaces.