@article{13513, author = {Chuankun Zhang and Lars von der Wense and Jack Doyle and Jacob Higgins and Tian Ooi and Hans Friebel and Jun Ye and R. Elwell and J. Terhune and H. Morgan and A. Alexandrova and H. Tan and Andrei Derevianko and Eric Hudson}, title = {^{229}ThF_4 thin films for solid-state nuclear clocks}, abstract = {

After nearly fifty years of searching, the vacuum ultraviolet 229Th nuclear isomeric transition has recently been directly laser excited [1,2] and measured with high spectroscopic precision [3]. Nuclear clocks based on this transition are expected to be more robust [4,5] than and may outperform [6,7] current optical atomic clocks. They also promise sensitive tests for new physics beyond the standard model [5,8,9]. In light of these important advances and applications, a dramatic increase in the need for 229Th spectroscopy targets in a variety of platforms is anticipated. However, the growth and handling of high-concentration 229Th-doped crystals [5] used in previous measurements [1-3,10] are challenging due to the scarcity and radioactivity of the 229Th material. Here, we demonstrate a potentially scalable solution to these problems by demonstrating laser excitation of the nuclear transition in 229ThF4 thin films grown with a physical vapor deposition process, consuming only micrograms of 229Th material. The 229ThF4 thin films are intrinsically compatible with photonics platforms and nanofabrication tools for integration with laser sources and detectors, paving the way for an integrated and field-deployable solid-state nuclear clock with radioactivity up to three orders of magnitude smaller than typical \thor-doped crystals [1-3,10]. The high nuclear emitter density in 229ThF4 also potentially enables quantum optics studies in a new regime. Finally, we describe the operation and present the estimation of the performance of a nuclear clock based on a defect-free ThF4 crystal.

}, year = {2024}, journal = {Nature}, volume = {in press}, month = {2024-12-1}, url = {https://arxiv.org/abs/2410.01753}, }