A MEMS-based device for trapped-ion quantum network nodes

As we move from fundamental research on quantum physics toward a new era of quantum technologies, efforts are underway to translate proof-of-principle laboratory experiments into compact, scalable devices. Within this project, we focus on constructing a scalable quantum interface between trapped ions one of the leading platforms for quantum technologies and single photons. Such interfaces are expected to be an integral part of future quantum networks. We will test an ion trap based on microelectromechanical systems (MEMS), which are devices with very small moving parts, based on fabrication technologies from the semiconductor industry. These MEMS technologies will allow us to integrate two optical fibers into the ion trap and to adjust the position of each fiber. Each fiber will be coated with a highly reflective mirror, and by placing the fibers opposite to one another, we can form a so-called optical resonator. The resonator will allows us to collect single particles of light, known as photons, from a single ionized calcium atom. It will also allow us to deliver photons efficiently to the ion and to control the quantum-mechanical interactions between ions and photons. The key question we will explore is whether this miniaturized device can compete with the current performance of much bulkier, hand-built laboratory setups. If so, it may enable quantum communication in between long-distance networks of ions, allowing us to achieve tasks that are not possible over todays communication networks. With international collaborators, we have recently conducted a feasibility study of the proposed device, with promising results. This project now allows us to test the device in practice. In the process, we will develop new techniques that are broadly relevant for quantum technologies, including new laser machining methods for fiber resonators and the integration of waveguides with ion traps.