Integrated photonics in trapped-ion systems are critical for the realization of applications such as portable optical atomic clocks and scalable quantum computers. However, system-level integration of all required functionalities remains a key challenge. In this work, we demonstrate an autonomously operating optical clock having a short-term frequency instability of 3.14(5)×10−14/τ using an ensemble of four 171Yb+ ions trapped in a multi-site surface-electrode trap at room temperature. All clock operations are performed with light delivered via on-chip waveguides. We showcase the system's resilience through sustained, autonomous operation featuring automated ion shuttling and reloading to mitigate ion loss during interleaved clock measurements. This work paves the way beyond component-level functionality to establish a viable and robust architecture for the next generation of portable, multi-ion quantum sensors and computers.
Atomic clocks are precision timekeeping devices that form the basis for modern communication and navigation. While many atomic clocks are room-sized systems requiring bulky free space optics and detectors, the Trapped-lon Clock using Technology-On-Chip (TICTOC) project integrates these components into Sandia's existing surface trap technology via waveguides for beam delivery and avalanche photodiodes for light detection. Taking advantage of a multi-ensemble clock interrogation approach, we expect to achieve record time stability (< 1 ns error per year) in a compact (< /1 2 L) clock. Here, we present progress on the development of the integrated devices and recent trapped ion demonstrations.
Trapped ions hold promise as the basis of highly accurate clocks and other quantum sensors. However, many real-world applications for quantum sensing require miniaturized, environmentally robust devices that can operate in the field. The significant experimental overhead imposed by free-space optics for control laser light delivery and collection has been an impediment to truly compact trapped-ion based clocks and sensors. The use of integrated technologies—including photonic waveguides, single-photon avalanche detectors (SPADs) and integrated electronics—provides a potential pathway towards overcoming these obstacles. I will discuss MIT Lincoln Laboratory’s recent efforts in this area, including demonstrations of integrated trapped-ion light delivery and collection and prospects for combining these technologies into a single chip-based trapped-ion reference.