Optimisation of Scalable Ion-Cavity Interfaces for Quantum Photonic Networks

Abstract

In the design optimisation of ion-cavity interfaces for quantum networking applications, difficulties occur due to the many competing figures of merit and highly interdependent design constraints, many of which present 'soft-limits', amenable to improvement at the cost of engineering time. In this work we present a systematic approach to this problem which offers a means to identify efficient and robust operating regimes, and to elucidate the trade-offs involved in the design process, allowing engineering efforts to be focused on the most sensitive and critical parameters. We show that in many relevant cases it is possible to approximately separate the geometric aspects of the cooperativity from those associated with the atomic system and the mirror surfaces themselves, greatly simplifying the optimisation procedure. Although our approach to optimisation can be applied to most operating regimes, here we consider cavities suitable for typical ion trapping experiments, and with substantial transverse misalignment of the mirrors. We find that cavities with mirror misalignments of many micrometres can still offer very high photon extraction efficiencies, offering an appealing route to the scalable production of ion-cavity interfaces for large scale quantum networks.

Multi-resonant open-access micro-cavity arrays for light matter interaction

“…We consider limits to cavity scalability in two broad classes: those which impact the generation of distributed entanglement across a quantum network and those that add complexity to the fabrication or operation within a laboratory environment. With regard to the first concern, a key metric of performance for a cavity-based network interface is its photon extraction efficiency, which, depending on the specific network architecture, will place a limit on the rate of heralded entanglement between spatially separated emitters [14]. Photons generated within an FFPC are inherently coupled to a fibre-guided mode, providing direct connectivity to an optical network.…”