On-Chip Rare-Earth Ion Architecture for Microwave to Optical Transduction

Quantum interconnects that generate entanglement between disparate quantum systems present opportunities for powerful and highly scalable quantum technologies. Rare-earth ions (REIs) in transparent crystals are an appealing platform in which to engineer high performance quantum interconnects particularly because of their ability to coherently transduce between microwave and optical photons. We present an on-chip REI architecture that integrates planar microwave technology with photonic waveguides and cavities: a versatile module for integrated quantum devices.
We fabricate nanophotonic waveguides and cavities using focused ion beam milling of yttrium vanadate crystals doped with Nd, Yb, or Er. The photonic components are positioned within microwave coplanar waveguides and cavities that allow coupling to the ions’ electron and nuclear spins. The achievement of optically detected magnetic resonance in these integrated devices will be presented along with the preliminary experiments demonstrating coherent microwave to optical conversion using Raman heterodyne spectroscopy. We characterize the performance of the devices and discuss the roadmap for increasing the efficiency and fidelity towards the quantum regime.